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Sample records for batio3 thin films

  1. Microstructural properties of BaTiO3 ceramics and thin films

    International Nuclear Information System (INIS)

    Fundora C, A.; Portelles, J.J.; Siqueiros, J.M.

    2000-01-01

    A microstructural study of BaTiO 3 ceramics obtained by the conventional ceramic method is presented. Targets were produced to grow BaTiO 3 thin films by pulsed laser deposition on Pt/Ti/Si (100) substrates. X-ray diffraction, Auger Electron Spectroscopy, X-ray Photon Spectroscopy and Scanning Electron Microscopy were used to study the properties of the BaTiO 3 ceramic samples and thin films, as deposited and after an annealing process. (Author)

  2. Excimer laser assisted re-oxidation of BaTiO3 thin films on Ni metal foils

    International Nuclear Information System (INIS)

    Bharadwaja, S. S. N.; Ko, S. W.; Qu, W.; Clark, T.; Rajashekhar, A.; Motyka, M.; Podraza, N.; Randall, C. A.; Trolier-McKinstry, S.

    2016-01-01

    Excimer laser assisted re-oxidation for reduced, crystallized BaTiO 3 thin films on Ni-foils was investigated. It was found that the BaTiO 3 can be re-oxidized at an oxygen partial pressure of ∼50 mTorr and substrate temperature of 350 °C without forming a NiO x interface layer between the film and base metal foil. The dielectric permittivity of re-oxidized films was >1000 with loss tangent values <2% at 100 Hz, 30 mV rms excitation signal. Electron Energy Loss Spectroscopy indicated that BaTiO 3 thin films can be re-oxidized to an oxygen stoichiometry close to ∼3 (e.g., stoichiometric). High resolution cross sectional transmission electron microscopy showed no evidence of NiO x formation between the BaTiO 3 and the Ni foil upon excimer laser re-oxidation. Spectroscopic ellipsometry studies on laser re-oxidized [001] C and [111] C BaTiO 3 single crystals indicate that the re-oxidation of BaTiO 3 single crystals is augmented by photo-excitation of the ozone, as well as laser pulse induced temperature and local stress gradients

  3. Pulsed Laser Deposition of BaTiO3 Thin Films on Different Substrates

    Directory of Open Access Journals (Sweden)

    Yaodong Yang

    2010-01-01

    Full Text Available We have studied the deposition of BaTiO3 (BTO thin films on various substrates. Three representative substrates were selected from different types of material systems: (i SrTiO3 single crystals as a typical oxide, (ii Si wafers as a semiconductor, and (iii Ni foils as a magnetostrictive metal. We have compared the ferroelectric properties of BTO thin films obtained by pulsed laser deposition on these diverse substrates.

  4. Hydrothermal–galvanic couple synthesis of directionally oriented BaTiO3 thin films on TiN-coated substrates

    International Nuclear Information System (INIS)

    Yang, Chia-Jung; Tsai, Di-You; Chan, Pei-Hsuan; Wu, Chu-Tsun; Lu, Fu-Hsing

    2013-01-01

    BaTiO 3 films were synthesized on TiN-coated Si substrate below 100 °C by a hydrothermal–galvanic couple technique in barium contained alkaline solutions. X-ray diffraction and electron backscatter diffraction results show that the BaTiO 3 thin films were directionally oriented grown on the TiN/Si substrates, i.e., (111) BaTiO 3 over (111) TiN. The surface morphologies revealed that BaTiO 3 nucleated and grew over the TiN surface with a single layer. From kinetic analyses, the growth rates of BaTiO 3 films prepared by the hydrothermal–galvanic couple technique were faster than a hydrothermal method. The galvanic effects were confirmed by investigating the induced currents and energies. The galvanic currents were generated and controlled by both the dissolution of TiN and the formation of BaTiO 3 . The output electric energies increased rapidly with the reaction time and leveled off at the full coverage of BaTiO 3 . - Highlights: • Cubic BaTiO 3 films are synthesized by a hydrothermal–galvanic couple method (HT–GC). • Growth rates of BaTiO 3 films made by HT–GC are faster than a hydrothermal method. • BaTiO 3 films are directionally oriented grown on the TiN/Si substrates. • Galvanic currents are controlled by dissolution of TiN and formation of BaTiO 3

  5. Ferroelectric BaTiO3 thin films on Ti substrate fabricated using pulsed-laser deposition.

    Science.gov (United States)

    He, J; Jiang, J C; Liu, J; Collins, G; Chen, C L; Lin, B; Giurgiutiu, V; Guo, R Y; Bhalla, A; Meletis, E I

    2010-09-01

    We report on the fabrication of ferroelectric BaTiO3 thin films on titanium substrates using pulsed laser deposition and their microstructures and properties. Electron microscopy studies reveal that BaTiO3 films are composed of crystalline assemblage of nanopillars with average cross sections from 100 nm to 200 nm. The BaTiO3 films have good interface structures and strong adhesion with respect to Ti substrates by forming a rutile TiO2 intermediate layer with a gradient microstructure. The room temperature ferroelectric polarization measurements show that the as-deposited BTO films possess nearly the same spontaneous polarization as the bulk BTO ceramics indicating formation of ferroelectric domains in the films. Successful fabrication of such ferroelectric films on Ti has significant importance for the development of new applications such as structural health monitoring spanning from aerospace to civil infrastructure. The work can be extended to integrate other ferroelectric oxide films with various promising properties to monitor the structural health of materials.

  6. Synthesis and characterization of multilayered BaTiO3/NiFe2O4 thin films

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    Branimir Bajac

    2013-03-01

    Full Text Available Presented research was focused on the fabrication of multiferroic thin film structures, composed of ferrielectric barium titanate perovskite phase and magnetostrictive nickel ferrite spinel phase. The applicability of different, solution based, deposition techniques (film growth from solution, dip coating and spin coating for thefabrication of multilayered BaTiO3 /NiFe2O4 thin films was investigated. It was shown that only spin coating produces films of desired nanostructure, thickness and smooth and crackfree surfaces.

  7. Preparation and optical properties of gold-dispersed BaTiO3 thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kineri, T; Mori, M [TDK Corp., Tokyo (Japan). R and D Center; Kadono, K; Sakaguchi, T; Miya, M; Wakabayashi, H [Osaka National Research Inst., Osaka (Japan); Tsuchiya, T [Science Univ. of Tokyo, Tokyo (Japan). Faculty of Industrial Science and Technology

    1993-12-01

    Recently, metal or semiconductor-doped glasses were widely studied because of their large resonant third-order nonlinearity. These glasses are utilized in an optical information field as all optical logic devices in the future. The gold-doped glass films or thin layers have a large third-order nonlinear susceptibility [chi] and are prepared by r.f. sputtering method, etc. The optical properties, particularly the refractive index or dielectric constant of the matrix, are very important for the optical nonlinearity of these materials. In this study, gold-dispersed BaTiO3 thin films and gold-dispersed SiO2 thin films are prepared using r.f. magnetron sputtering method, and the optical properties of the films are compared. The [chi] of the films are measured and the effect of the matrix of the films on [chi] is investigated. The headings in the paper are: Introduction, Experimental procedure, Results, Discussion, and Conclusion. 13 refs., 9 figs.

  8. Dynamics of ferroelectric nanodomains in BaTiO3 epitaxial thin films via piezoresponse force microscopy

    International Nuclear Information System (INIS)

    Pertsev, N A; Petraru, A; Kohlstedt, H; Waser, R; Bdikin, I K; Kiselev, D; Kholkin, A L

    2008-01-01

    Ferroelectric nanodomains were created in BaTiO 3 thin films by applying a voltage to a sharp conducting tip of a scanning force microscope (SFM). The films were epitaxially grown on SrRuO 3 -covered (001)-oriented SrTiO 3 substrates by a high-pressure sputtering. They appeared to be single-crystalline with the (001) crystallographic orientation relative to the substrate. Using the piezoresponse mode of the SFM to detect the out-of-plane film polarization, the domain sizes were measured as a function of the applied writing voltage and the pulse time. It was found that the time dependence of the domain diameter in a 60 nm thick BaTiO 3 film deviates significantly from the logarithmic law observed earlier in Pb(Zr 0.2 Ti 0.8 )O 3 (PZT) films. At a given writing time, the domain size increases nonlinearly with increasing applied voltage, in contrast to the linear behavior reported earlier for PZT films and LiNbO 3 single crystals. The dynamics of domain growth is analyzed theoretically taking into account the strong inhomogeneity of the external electric field in the film and the influence of the bottom electrode. It is shown that the observed writing time and voltage dependences of the domain size can be explained by the domain-wall creep in the presence of random-bond disorder

  9. Effect of crystal orientation on the phase diagrams, dielectric and piezoelectric properties of epitaxial BaTiO3 thin films

    Directory of Open Access Journals (Sweden)

    Huaping Wu

    2016-01-01

    Full Text Available The influence of crystal orientations on the phase diagrams, dielectric and piezoelectric properties of epitaxial BaTiO3 thin films has been investigated using an expanded nonlinear thermodynamic theory. The calculations reveal that crystal orientation has significant influence on the phase stability and phase transitions in the misfit strain-temperature phase diagrams. In particular, the (110 orientation leads to a lower symmetry and more complicated phase transition than the (111 orientation in BaTiO3 films. The increase of compressive strain will dramatically enhance the Curie temperature TC of (110-oriented BaTiO3 films, which matches well with previous experimental data. The polarization components experience a great change across the boundaries of different phases at room temperature in both (110- and (111-oriented films, which leads to the huge dielectric and piezoelectric responses. A good agreement is found between the present thermodynamics calculation and previous first-principles calculations. Our work provides an insight into how to use crystal orientation, epitaxial strain and temperature to tune the structure and properties of ferroelectrics.

  10. Structural characterization and dielectric properties of BaTiO3 thin films obtained by spin coating

    Directory of Open Access Journals (Sweden)

    Branimir Bajac

    2014-12-01

    Full Text Available Barium titanate thin films were prepared by spin coating deposition technique of an acetic precursor sol and sintered at 750, 900 and 1050 °C. Phase composition of the obtained thin films was characterized by X-ray diffraction and Raman spectroscopy. Their morphology was analysed by scanning electron microscopy and atomic force microscopy. Dielectric properties of thin films sintered at 750 and 900 °C were characterized by LCD device, where the influence of sintering temperature on dielectric permittivity and loss tangent was inspected. It was concluded that higher sintering temperature increases grain size and amount of tetragonal phase, hence higher relative permittivity was recorded. The almost constant relative permittivity in the measured frequency (800 Hz–0.5 MHz and temperature (25–200 °C ranges as well as low dielectric loss are very important for the application of BaTiO3 films in microelectronic devices.

  11. Ferroelectric properties of NaNbO3-BaTiO3 thin films deposited on SrRuO3/(001)SrTiO3 substrate by pulsed laser deposition

    International Nuclear Information System (INIS)

    Yamazoe, Seiji; Oda, Shinya; Sakurai, Hiroyuki; Wada, Takahiro; Adachi, Hideaki

    2009-01-01

    (NaNbO 3 ) 1-x (BaTiO 3 ) x (NN-xBT) thin films with low BaTiO 3 (BT) concentrations x (x=0.05 and 0.10) were fabricated on SrRuO 3 /(001)SrTiO 3 (SRO)/(001)STO) substrate by pulsed laser deposition (PLD). X-ray diffraction pattern (XRD) and transmission electron diffraction pattern (TED) showed that NN-0.10BT thin film was epitaxially grown on SRO/(001)STO substrate with a crystallographic relationship of [001] NN-xBT parallel [001] STO . From reciprocal space maps, the lattice parameters of the out-of-plane direction of NN-xBT thin films became larger with an increase in BT concentration, although the lattice parameter of the in-plane was hardly changed by the BT concentration. The value of relative dielectric constant ε r of the NN-xBT thin films were increased with BT concentration. The ε r and the dielectric loss tanδ of NN-0.10BT were 1220 and 0.02 at 1 kHz, respectively. The P-E hysteresis loops of the NN-xBT thin films showed clear ferroelectricity. Although the value of remanent polarization P r decreased with the BT concentration, the behaviors of ε r , P r , and coercive electric field E c of the NN-xBT thin films against the BT concentration accorded with those of NN-xBT ceramics, in which NN-0.10BT ceramics exhibited the largest piezoelectric property. Therefore, the NN-0.10BT thin film is expected to show high piezoelectricity. (author)

  12. Growth of BaTiO3-PVDF composite thick films by using aerosol deposition

    Science.gov (United States)

    Cho, Sung Hwan; Yoon, Young Joon

    2016-01-01

    Barium titanate (BaTiO3)-polyvinylidene fluoride (PVDF) composite thick films were grown by using aerosol deposition at room temperature with BaTiO3 and PVDF powders. To produce a uniform composition in ceramic and polymer composite films, which show a substantial difference in specific gravity, we used PVDF-coated BaTiO3 powders as the starting materials. An examination of the microstructure confirmed that the BaTiO3 were well distributed in the PVDF matrix in the form of a 0 - 3 compound. The crystallite size in the BaTiO3-PVDF composite thick films was 5 ˜ 50 times higher than that in pure BaTiO3 thick films. PVDF plays a role in suppressing the fragmentation of BaTiO3 powder during the aerosol deposition process and in controlling the relative permittivity.

  13. Self-Organized Ni Nanocrystal Embedded in BaTiO3 Epitaxial Film

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    Ge FF

    2010-01-01

    Full Text Available Abstract Ni nanocrystals (NCs were embedded in BaTiO3 epitaxial films using the laser molecular beam epitaxy. The processes involving the self-organization of Ni NCs and the epitaxial growth of BaTiO3 were discussed. With the in situ monitoring of reflection high-energy electron diffraction, the nanocomposite films were engineered controllably by the fine alternation of the self-organization of Ni NCs and the epitaxial growth of BaTiO3. The transmission electron microscopy and the X-ray diffraction characterization confirmed that the composite film consists of the Ni NCs layers alternating with the (001/(100-oriented epitaxial BaTiO3 separation layers.

  14. Two steps hydrothermal growth and characterisations of BaTiO3 films composed of nanowires

    Science.gov (United States)

    Zawawi, Che Zaheerah Najeehah Che Mohd; Salleh, Shahril; Oon Jew, Lee; Tufail Chaudhary, Kashif; Helmi, Mohamad; Safwan Aziz, Muhammad; Haider, Zuhaib; Ali, Jalil

    2018-05-01

    Barium titanate (BaTiO3) films composed of nanowires have gained considerable research interest due to their lead-free composition and strong energy conversion efficiency. BaTiO3 films can be developed with a simple two steps hydrothermal reactions, which are low cost effective. In this research, BaTiO3 films were fabricated on titanium foil through two steps hydrothermal method namely, the growth of TiO2 and followed by BaTiO3 films. The structural evolutions and the dielectric properties of the films were investigated as well. The structural evolutions of titanium dioxide (TiO2) and BaTiO3 nanowires were characterized using X-ray diffraction and scanning electron microscopy. First step of hydrothermal reaction, TiO2 nanowires were prepared in varied temperatures of 160 °C, 200 °C and 250 °C respectively. Second step of hydrothermal reaction was performed to produce a layer of BaTiO3 films.

  15. Hydrothermal growth of highly textured BaTiO3 films composed of nanowires

    International Nuclear Information System (INIS)

    Zhou Zhi; Tang Haixiong; Sodano, Henry A; Lin Yirong

    2013-01-01

    Textured barium titanate (BaTiO 3 ) films are attracting immense research interest due to their lead-free composition and excellent piezoelectric and dielectric properties. Most synthesis methods for these films require a high temperature, leading to the formation of a secondary phase and an overall decrease in the electrical properties of the ceramic. In order to alleviate these issues, a novel fabrication method is introduced by transferring oriented rutile TiO 2 nanowires to a textured BaTiO 3 film at temperatures below 160 °C. The microstructure and thickness of the fabricated BaTiO 3 films were characterized by scanning electron microscopy, and the crystal structure and degree of orientation were evaluated by x-ray diffraction patterns using the Lotgering method. It is shown that the thickness of the BaTiO 3 film can be controlled by the length of TiO 2 nanowire array template, and the degree of orientation of the textured BaTiO 3 films is highly dependent on the film thickness; the crystallographic orientation has been measured to reach up to 87%. The relative dielectric constant (ε r = 1300) and ferroelectric properties (P r = 2.7 μC cm −2 , E c = 4.0 kV mm −1 ) of the textured BaTiO 3 films were also characterized to demonstrate their potential application in sensors, random access memory, and micro-electromechanical systems. (paper)

  16. Multiphase nanodomains in a strained BaTiO3 film on a GdScO3 substrate

    Science.gov (United States)

    Kobayashi, Shunsuke; Inoue, Kazutoshi; Kato, Takeharu; Ikuhara, Yuichi; Yamamoto, Takahisa

    2018-02-01

    Controlling the crystal structure of ferroelectric materials via epitaxial strain, which is a well-known technique in strain engineering, can lead to the formation of unique domain structures generating non-intrinsic phenomena such as electronic conductivity, photovoltages, and enhanced piezoelectric characteristics. Strained BaTiO3 films are promising ferroelectric materials as theoretical modeling predicts that different domain morphologies can introduce additional properties not observed in conventional BaTiO3 ceramics. To rationally design materials for practical application, a thorough understanding of the formation mechanisms and stabilities of different domain structures in strained BaTiO3 films is required. However, there have been very few experimental reports on this topic, and details about the domain structures in strained BaTiO3 films are currently lacking. In this paper, we report multiphase nanodomains in a strained BaTiO3 film deposited on an orthorhombic GdScO3 substrate. The phase-transition behavior of the strained BaTiO3 film reveals that it contains multiple phases at room temperature; the film first undergoes a phase-transition upon heating at around 550 K, and then a paraelectric phase forms at temperatures above 690 K. A picometer-scale analysis of the Ti ion displacements, using an advanced scanning transmission electron microscopy technique, is used to characterize the complex multiphase nanodomains, providing useful insights into the control of domain structures in BaTiO3 films by applying epitaxial strain.

  17. On stoichiometry and intermixing at the spinel/perovskite interface in CoFe2O4/BaTiO3 thin films.

    Science.gov (United States)

    Tileli, Vasiliki; Duchamp, Martial; Axelsson, Anna-Karin; Valant, Matjaz; Dunin-Borkowski, Rafal E; Alford, Neil McN

    2015-01-07

    The performance of complex oxide heterostructures depends primarily on the interfacial coupling of the two component structures. This interface character inherently varies with the synthesis method and conditions used since even small composition variations can alter the electronic, ferroelectric, or magnetic functional properties of the system. The focus of this article is placed on the interface character of a pulsed laser deposited CoFe2O4/BaTiO3 thin film. Using a range of state-of-the-art transmission electron microscopy methodologies, the roles of substrate morphology, interface stoichiometry, and cation intermixing are determined on the atomic level. The results reveal a surprisingly uneven BaTiO3 substrate surface formed after the film deposition and Fe atom incorporation in the top few monolayers inside the unit cell of the BaTiO3 crystal. Towards the CoFe2O4 side, a disordered region extending several nanometers from the interface was revealed and both Ba and Ti from the substrate were found to diffuse into the spinel layer. The analysis also shows that within this somehow incompatible composite interface, a different phase is formed corresponding to the compound Ba2Fe3Ti5O15, which belongs to the ilmenite crystal structure of FeTiO3 type. The results suggest a chemical activity between these two oxides, which could lead to the synthesis of complex engineered interfaces.

  18. Origin of thermally stable ferroelectricity in a porous barium titanate thin film synthesized through block copolymer templating

    Directory of Open Access Journals (Sweden)

    Norihiro Suzuki

    2017-07-01

    Full Text Available A porous barium titanate (BaTiO3 thin film was chemically synthesized using a surfactant-assisted sol-gel method in which micelles of amphipathic diblock copolymers served as structure-directing agents. In the Raman spectrum of the porous BaTiO3 thin film, a peak corresponding to the ferroelectric tetragonal phase was observed at around 710 cm−1, and it remained stable at much higher temperature than the Curie temperature of bulk single-crystal BaTiO3 (∼130 °C. Measurements revealed that the ferroelectricity of the BaTiO3 thin film has high thermal stability. By analyzing high-resolution transmission electron microscope images of the BaTiO3 thin film by the fast Fourier transform mapping method, the spatial distribution of stress in the BaTiO3 framework was clearly visualized. Careful analysis also indicated that the porosity in the BaTiO3 thin film introduced anisotropic compressive stress, which deformed the crystals. The resulting elongated unit cell caused further displacement of the Ti4+ cation from the center of the lattice. This displacement increased the electric dipole moment of the BaTiO3 thin film, effectively enhancing its ferro(piezoelectricity.

  19. Ferroelectric properties of BaTiO3/PbZr0.2Ti.08O3 bilayer thin film

    Science.gov (United States)

    Salev, Pavel; Yang, Chun; Grigoriev, Alexei

    2014-03-01

    The thin film ferroelectric BaTiO3/PbZr0.2Ti0.8O3 bilayer was epitaxially grown on SrRuO3/SrTiO3 substrate by RF sputtering. Electrical measurements of polarization switching revealed two different switching regimes - a small ferroelectric hysteresis loop at low applied voltage and a larger loop at a high voltage. The measured dielectric permittivity corresponds to weak electrostatic coupling between two layers according to Landau-Ginsburg-Devonshire theory. This weak coupling may allow for independent polarization states to exist in individual layers. This can lead to stable head-to-head and tail-to-tail polarization domain configurations, which would explain the two switching regimes observed in electrical measurements. The compensation of polarization gradient across the interface can be explained by the enhancement of interface charge carrier density due to strong bending of electron energy bands. This work was supported by NSF award DMR-1057159.

  20. Epitaxial c-axis oriented BaTiO3 thin films on SrTiO3-buffered Si(001) by atomic layer deposition

    International Nuclear Information System (INIS)

    Ngo, Thong Q.; McDaniel, Martin D.; Ekerdt, John G.; Posadas, Agham B.; Demkov, Alexander A.; Hu, Chengqing; Yu, Edward T.; Bruley, John

    2014-01-01

    Atomic layer deposition (ALD) of epitaxial c-axis oriented BaTiO 3 (BTO) on Si(001) using a thin (1.6 nm) buffer layer of SrTiO 3 (STO) grown by molecular beam epitaxy is reported. The ALD growth of crystalline BTO films at 225  °C used barium bis(triisopropylcyclopentadienyl), titanium tetraisopropoxide, and water as co-reactants. X-ray diffraction (XRD) reveals a high degree of crystallinity and c-axis orientation of as-deposited BTO films. Crystallinity is improved after vacuum annealing at 600  °C. Two-dimensional XRD confirms the tetragonal structure and orientation of 7–20-nm thick films. The effect of the annealing process on the BTO structure is discussed. A clean STO/Si interface is found using in-situ X-ray photoelectron spectroscopy and confirmed by cross-sectional scanning transmission electron microscopy. The capacitance-voltage characteristics of 7–20 nm-thick BTO films are examined and show an effective dielectric constant of ∼660 for the heterostructure

  1. Nanocomposites of ferroelectric polymers with surface-hydroxylated BaTiO 3 nanoparticles for energy storage applications

    KAUST Repository

    Almadhoun, Mahmoud Nassar Mahmoud

    2012-01-01

    A facile surface hydroxylation treatment using hydrogen peroxide to modify the surface of BaTiO 3 nanofillers dispersed in a ferroelectric copolymer host has been investigated. We demonstrate that the surface functionalization of the BaTiO 3 nanofillers (<100 nm) with hydroxyl groups results in as much as two orders of magnitude reduction in the leakage current of nanocomposite thin-film capacitors. This reduction is observed concurrently with the enhancement of the effective permittivity and breakdown strength of the thin-film nanocomposites. Surface modified BaTiO 3 particles display better dispersion within the polymer matrix, resulting in enhanced relative permittivity and reduced dielectric loss. The dielectric behavior of the nanocomposite films containing up to 30 vol.% BaTiO 3 agreed well with the Bruggeman model. These results demonstrate the potential of facile surface hydroxylation of nanoparticles towards the fabrication of higher energy-density nanocomposites. © 2012 The Royal Society of Chemistry.

  2. Effects of Nb and Sr doping on crystal structure of epitaxial BaTiO3 thin films on MgO substrates

    International Nuclear Information System (INIS)

    Kim, Yongsam; Chen, Chunhua; Saiki, Atsushi; Wakiya, Naoki; Shinozaki, Kazuo; Mizutani, Nobuyasu

    2002-01-01

    Niobium (Nb) and strontium (Sr) doped barium titanate (BT) films were deposited by radio frequency (RF) magnetron sputtering with Nb and Sr doped BT ceramic targets, respectively. The effect of Nb and Sr doping on the crystal structure of epitaxial BaTiO 3 thin films on MgO substrates was investigated. The crystal structure of the films was examined using the reciprocal space mapping measurement. All the films exhibit a cube-on-cube relation with respect to the substrates. As the amount of doped Sr increased, both of the in-plane and out-of-plane lattice constants of Sr doped BT films slowly approached the BT bulk values. On the other hand, the lattice constants of Nb doped BT films were rapidly coming close to the bulk values. These indicated that the lattices of doped BT films were relaxed as the amount of doped elements increased. In addition, Nb doping had greater influence on the relaxation of the films than Sr doping for the same content of dopant. (author)

  3. X-ray line profile analysis of BaTiO3 thin film prepared by sol-gel deposition

    Science.gov (United States)

    Ooi, Zeen Vee; Saif, Ala'eddin A.; Wahab, Yufridin; Jamal, Zul Azhar Zahid

    2017-04-01

    Barium titanate (BaTiO3) thin film was prepared using sol-gel method and spun-coated on SiO2/Si substrate. The phase and crystallinity of the synthesized film were identified using X-ray diffractometer (XRD), which scanned at the range of 20° to 60°. The phase and lattice parameters of the fabricated film were extracted from the recorded XRD patterns using lattice geometry equations. The crystallite size and lattice strain were determined using X-ray line profile analysis (XLPA) with various approaches. The Scherrer equation was applied to the perovskite peaks of the film to explore the size contribution on the peak broadening. Meanwhile, the Williamson-Hall and size-strain plot (SSP) methods were used to review two main independent contributions, i.e. crystallite sizes and lattice strain, on the X-ray line broadening. From the analysis, it is found that Scherrer method gives smallest crystallite size value by ignoring the strain-induced broadening effect. On the other hand, Williamson-Hall and SSP graphs revealed the existence of the lattice strain within the film, which contributes to the broadening in the Bragg peak. The results that analyzed via both techniques show a linear trend with all data points fitted. However, result obtained from SSP method gives better settlement due to the best fit of the data.

  4. Growth and self-assembly of BaTiO3 nanocubes for resistive switching memory cells

    International Nuclear Information System (INIS)

    Chu, Dewei; Lin, Xi; Younis, Adnan; Li, Chang Ming; Dang, Feng; Li, Sean

    2014-01-01

    In this work, the self-assembled BaTiO 3 nanocubes based resistive switching memory capacitors are fabricated with hydrothermal and drop-coating approaches. The device exhibits excellent bipolar resistance switching characteristics with ON/OFF ratio of 58–70, better reliability and stability over various polycrystalline BaTiO 3 nanostructures. It is believed that the inter cube junctions is responsible for such a switching behaviour and it can be described by the filament model. The effect of film thickness on switching ratio (ON/OFF) was also investigated in details. - Graphical abstract: This work describes a novel resistive switching memory cell based on self-assembled BaTiO 3 nanocubes. - Highlights: • BaTiO 3 nanocubes were prepared by one step facile hydrothermal method. • Self-assembled BaTiO 3 nanocubes thin films were obtained by drop-coating approach. • The BaTiO 3 nanocubes show excellent resistive switching properties for memory applications

  5. Electrical properties of (1 0 0)-predominant BaTiO3 films derived from alkoxide solutions of two concentrations

    International Nuclear Information System (INIS)

    Guo Yiping; Suzuki, Kazuyuki; Nishizawa, Kaori; Miki, Takeshi; Kato, Kazumi

    2006-01-01

    Lead-free piezoelectric films with thickness larger than 1 μm integrated on silicon substrates have been receiving considerable attention because of environmental concerns and their potential applications in microelectromechanical systems. We demonstrate that, by chemical solution deposition, it is possible to process (1 0 0)-predominant 1 μm BaTiO 3 films on LaNiO 3 /Pt/TiO x /SiO 2 /Si substrates using thinner high-crystallinity columnar BaTiO 3 films as buffer layers. We point out that this kind of buffer layer prepared with a lower concentration solution on the surface of an LaNiO 3 /Pt electrode is effective in enhancing the crystallinity and orientation degree of final BaTiO 3 films prepared with a higher concentration solution. The 1 μm BaTiO 3 films show good dielectric and insulating characteristics against an applied field, and the conduction current shows Schottky emission behavior at modest voltage and space-charge-limited behavior at higher voltage. We also demonstrate that the (1 0 0)-predominant 1 μm BaTiO 3 films have excellent piezoelectric properties: piezoelectric coefficients d 33 higher than 50 pm/V have been determined for the bare films using atomic force microscopy, which are comparable to those of Pb(Zr,Ti)O 3 films. These results indicate that the (1 0 0)-predominant BaTiO 3 films should be promising candidates for microelectromechanical systems applications

  6. Dielectric and piezoelectric properties of lead-free (Bi,Na)TiO3-based thin films

    Science.gov (United States)

    Abazari, M.; Safari, A.; Bharadwaja, S. S. N.; Trolier-McKinstry, S.

    2010-02-01

    Dielectric and piezoelectric properties of morphotropic phase boundary (Bi,Na)TiO3-(Bi,K)TiO3-BaTiO3 epitaxial thin films deposited on SrRuO3 coated SrTiO3 substrates were reported. Thin films of 350 nm thickness exhibited small signal dielectric permittivity and loss tangent values of 750 and 0.15, respectively, at 1 kHz. Ferroelectric hysteresis measurements indicated a remanent polarization value of 30 μC/cm2 with a coercive field of 85-100 kV/cm. The thin film transverse piezoelectric coefficient (e31,f) of these films after poling at 600 kV/cm was found to be -2.2 C/m2. The results indicate that these BNT-based thin films are a potential candidate for lead-free piezoelectric devices.

  7. Conduction Mechanisms in Multiferroic Multilayer BaTiO3/NiFe2O4/BaTiO3 Memristors

    Science.gov (United States)

    Samardzic, N.; Bajac, B.; Srdic, V. V.; Stojanovic, G. M.

    2017-10-01

    Memristive devices and materials are extensively studied as they offer diverse properties and applications in digital, analog and bio-inspired circuits. In this paper, we present an important class of memristors, multiferroic memristors, which are composed of multiferroic multilayer BaTiO3/NiFe2O4/BaTiO3 thin films, fabricated by a spin-coating deposition technique on platinized Si wafers. This cost-effective device shows symmetric and reproducible current-voltage characteristics for the actuating voltage amplitude of ±10 V. The origin of the conduction mechanism was investigated by measuring the electrical response in different voltage and temperature conditions. The results indicate the existence of two mechanisms: thermionic emission and Fowler-Nordheim tunnelling, which alternate with actuating voltage amplitude and operating temperature.

  8. Nucleation control and inhibition of BaTiO3 films using hydrothermal-electrochemical method

    International Nuclear Information System (INIS)

    Escobar, Ivan; Silva, Carmen; Silva, Eric; Vargas, Tomas; Fuenzalida, Victor

    1999-01-01

    The microstructure of BaTiO 3 films on titanium by the hydrothermal-electrochemical method was investigated using a three electrode high pressure electrochemical cell in a 0.2 M Ba(OH) 2 electrolyte at 150 0 C. The spontaneous initial linked to pure hydrothermal BaTiO 3 formation can be inhibited by cathodically protecting titanium electrode since its immersion in the electrolyte. The application of initial nucleation pulses of varying the cathodic potentials affected the grain size of the deposit. It is suggested that the formation of a titanium oxide layers is a necessary step previous to the nucleation of BaTiO 3

  9. Electric double layer transistors with ferroelectric BaTiO3 channels

    NARCIS (Netherlands)

    Ito, M.; Matsubara, Y.; Kozuka, Y.; Takahashi, K. S.; Kagawa, F.; Ye, J. T.; Iwasa, Y.; Ueno, K.; Tokura, Y.; Kawasaki, M.

    2014-01-01

    We report the surface conduction of a BaTiO3 thin film using electric double layer transistor (EDLT) structure. A transistor operation was observed at 220 K with an on/off ratio exceeding 10(5), demonstrating that ionic liquid gating is effective to induce carriers at the surface of ferroelectric

  10. Electrical properties of resistive switches based on Ba1-χSrχTiO3 thin films prepared by RF co-sputtering

    International Nuclear Information System (INIS)

    Marquez H, A.; Hernandez R, E.; Zapata T, M.; Guillen R, J.; Cruz, M. P.; Calzadilla A, O.; Melendez L, M.

    2010-01-01

    In this work, was proposed the use of Ba 1-χ Sr χ TiO 3 (0≤x≤1) thin films for the construction of metal-insulator-metal heterostructures; and their great potential for the development of non-volatile resistance memories (ReRAM) is shown. The deposition of Ba 1-χ Sr χ TiO 3 thin films was done by the RF co-sputtering technique using two magnetron sputtering cathodes with BaTiO 3 and SrTiO 3 targets. The chemical composition (x parameter) in the deposited Ba 1-χ Sr χ TiO 3 thin films was varied through the RF powder applied to the targets. The constructed metal-insulator-metal heterostructures were Al/Ba 1-χ Sr χ TiO 3 /nichrome. The I-V measurements of the heterostructures showed that their hysteretic characteristics change depending on the Ba/Sr ratio of the Ba 1-χ Sr χ TiO 3 thin films; the Ba/Sr ratio was determined by employing the energy dispersive spectroscopy; Sem micrographs showed that Ba 1-χ Sr χ TiO 3 thin films were uniform without cracks or pinholes. Additionally, the analysis of the X-ray diffraction results indicated the substitutional incorporation of Sr into the BaTiO 3 lattice and the obtainment of crystalline films for the entire range of the x values. (Author)

  11. Band-offsets at BaTiO3/Cu2O heterojunction and enhanced photoelectrochemical response: theory and experiment(Conference Presentation)

    Science.gov (United States)

    Sharma, Dipika; Satsangi, Vibha R.; Dass Kaura, Sahab; Shrivastav, Rohit; Waghmare, Umesh V.

    2016-10-01

    Band-offsets at BaTiO3/Cu2O heterojunction and enhanced photoelectrochemical response: theory and experiment Dipika Sharmaa, Vibha R. Satsangib, Rohit Shrivastava, Umesh V. Waghmarec, Sahab Dassa aDepartment of Chemistry, Dayalbagh Educational Institute, Agra-282 110 (India) bDepartment of Physics and Computer Sciences, Dayalbagh Educational Institute, Agra-282 110 (India) cTheoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560 064 (India) * Phone: +91-9219695960. Fax: +91-562-2801226. E-mail: drsahabdas@gmail.com. Study on photoelectrochemical activity of pristine BaTiO3, Cu2O and BaTiO3/Cu2O heterojunction has been carried out using DFT based band offsets and charge carriers effective mass calculations and their experimental verification. The results of DFT calculations show that BaTiO3 and Cu2O have staggered type band alignment after the heterojunction formation and high mobility of electrons in Cu2O as compared to the electrons in BaTiO3. Staggered type band edges alignment and high mobility of electrons and holes improved the separation of photo-generated charge carriers in BaTiO3/Cu2O heterojunction. To validate the theoretical results experiments were carried out on pristine BaTiO3, Cu2O and BaTiO3/Cu2O heterojunction with varying thickness of Cu2O. All samples were characterized by X- Ray Diffractometer, SEM and UV-Vis spectrometry. Nanostructured thin films of pristine BaTiO3, Cu2O and BaTiO3/Cu2O heterojunction were used as photoelectrode in the photoelectrochemical cell for water splitting reaction. Maximum photocurrent density of 1.44 mA/cm2 at 0.90 V/SCE was exhibited by 442 nm thick BaTiO3/Cu2O heterojunction photoelectrode Increased photocurrent density and enhanced photoconversion efficiency, exhibited by the heterojunction may be attributed to improved conductivity and enhanced separation of the photogenerated carriers at the BaTiO3/Cu2O interface. The experimental results and first

  12. Aggregate linear properties of ferroelectric ceramics and polycrystalline thin films: Calculation by the method of effective piezoelectric medium

    Science.gov (United States)

    Pertsev, N. A.; Zembilgotov, A. G.; Waser, R.

    1998-08-01

    The effective dielectric, piezoelectric, and elastic constants of polycrystalline ferroelectric materials are calculated from single-crystal data by an advanced method of effective medium, which takes into account the piezoelectric interactions between grains in full measure. For bulk BaTiO3 and PbTiO3 polarized ceramics, the dependences of material constants on the remanent polarization are reported. Dielectric and elastic constants are computed also for unpolarized c- and a-textured ferroelectric thin films deposited on cubic or amorphous substrates. It is found that the dielectric properties of BaTiO3 and PbTiO3 polycrystalline thin films strongly depend on the type of crystal texture. The influence of two-dimensional clamping by the substrate on the dielectric and piezoelectric responses of polarized films is described quantitatively and shown to be especially important for the piezoelectric charge coefficient of BaTiO3 films.

  13. Synchrotron X-ray studies of epitaxial ferroelectric thin films and nanostructures

    Science.gov (United States)

    Klug, Jeffrey A.

    The study of ferroelectric thin films is a field of considerable scientific and technological interest. In this dissertation synchrotron x-ray techniques were applied to examine the effects of lateral confinement and epitaxial strain in ferroelectric thin films and nanostructures. Three materials systems were investigated: laterally confined epitaxial BiFeO3 nanostructures on SrTiO3 (001), ultra-thin commensurate SrTiO 3 films on Si (001), and coherently strained films of BaTiO3 on DyScO3 (110). Epitaxial films of BiFeO3 were deposited by radio frequency magnetron sputtering on SrRuO3 coated SrTiO 3 (001) substrates. Laterally confined nanostructures were fabricated using focused ion-beam processing and subsequently characterized with focused beam x-ray nanodiffraction measurements with unprecedented spatial resolution. Results from a series of rectangular nanostructures with lateral dimensions between 500 nm and 1 mum and a comparably-sized region of the unpatterned BiFeO3 film revealed qualitatively similar distributions of local strain and lattice rotation with a 2-3 times larger magnitude of variation observed in those of the nanostructures compared to the unpatterned film. This indicates that lateral confinement leads to enhanced variation in the local strain and lattice rotation fields in epitaxial BiFeO3 nanostructures. A commensurate 2 nm thick film of SrTiO3 on Si was characterized by the x-ray standing wave (XSW) technique to determine the Sr and Ti cation positions in the strained unit cell in order to verify strain-induced ferroelectricity in SrTiO3/Si. A Si (004) XSW measurement at 10°C indicated that the average Ti displacement from the midpoint between Sr planes was consistent in magnitude to that predicted by a density functional theory (DFT) calculated ferroelectric structure. The Ti displacement determined from a 35°C measurement better matched a DFT-predicted nonpolar structure. The thin film extension of the XSW technique was employed to

  14. PLD of X7R for thin film capacitors

    International Nuclear Information System (INIS)

    Hino, Takanori; Matsumoto, Noriyuki; Nishida, Minoru; Araki, Takao

    2008-01-01

    Thin film capacitors with a thickness of 200 nm were prepared on SrTiO 3 (1 0 0), (1 1 0) and (1 1 1) single crystal substrates at a temperature of 973 K by pulsed laser deposition (PLD) using a KrF excimer laser in an O 2 -O 3 atmosphere with a gas pressure of 1 Pa using an X7R sintered target. As a result, perovskite BaTiO 3 solid solution films were obtained. In the X7R thin films on (1 0 0) and (1 1 0) SrTiO 3 , only diffraction peaks with strong intensities from BaTiO 3 (1 0 0) and (1 1 0), respectively, were observed. X7R films on SrTiO 3 (1 1 1) were grown epitaxially oriented to the crystal plane direction of the substrate by inserting an initial homoepitaxial SrTiO 3 layer with a thickness of 4 nm. The X7R/SrTiO 3 film capacitors yielded a large volumetric efficiency of 50 μF/mm 3 and a temperature coefficient of capacitance (TCC) of -1.3% to 1.3% which satisfies the EIA standard specifications for X7R

  15. Enhanced photoelectrochemical properties of 100 MeV Si8+ ion irradiated barium titanate thin films

    International Nuclear Information System (INIS)

    Solanki, Anjana; Choudhary, Surbhi; Satsangi, Vibha R.; Shrivastav, Rohit; Dass, Sahab

    2013-01-01

    Highlights: ► Effect of 100 MeV Si 8+ ion irradiation on photoelectrochemical (PEC) properties of BaTiO 3 thin films was studied. ► Films were deposited on Indium doped Tin Oxide (ITO) coated glass by sol–gel spin coating technique. ► Optimal irradiation fluence for best PEC response was 5 × 10 11 ion cm −2 . ► Maximum photocurrent density was observed to be 0.7 mA cm −2 at 0.4 V/SCE. ► Enhanced photo-conversion efficiency was due to maximum negative flatband potential, donor density and lowest resistivity. -- Abstract: Effects of high electronic energy deposition on the structure, surface topography, optical property and photoelectrochemical behavior of barium titanate (BaTiO 3 ) thin films were investigated by irradiating films with 100 MeV Si 8+ ions at different ion fluences in the range of 1 × 10 11 –2 × 10 13 ions cm −2 . BaTiO 3 thin films were deposited on indium tin oxide coated glass substrate by sol gel spin coating method. Irradiation induced modifications in the films were analyzed using the results from XRD, SEM, cross sectional SEM, AFM and UV–Vis spectrometry. Maximum photocurrent density of 0.7 mA cm −2 at 0.4 V/SCE and applied bias hydrogen conversion efficiency (ABPE) of 0.73% was observed for BaTiO 3 film irradiated at 5 × 10 11 ions cm −2 , which can be attributed to maximum negative value of the flatband potential and donor density and lowest resistivity

  16. A first-principles study of phase transitions in ultrathin films of BaTiO 3

    Indian Academy of Sciences (India)

    We determine the effects of film thickness, epitaxial strain and the nature of electrodes on ferroelectric phase transitions in ultrathin films of BaTiO3 using a first-principles effective Hamiltonian in classical molecular dynamics simulations. We present results for polarization and dielectric properties as a function of temperature ...

  17. Hybrid chitosan–Pluronic F-127 films with BaTiO3:Co nanoparticles: Synthesis and properties

    International Nuclear Information System (INIS)

    Fuentes, S.; Dubo, J.; Barraza, N.; González, R.; Veloso, E.

    2015-01-01

    In this study, magnetic BaTiO 3 :Co (BT:Co) nanoparticles prepared using a combined sol–gel–hydrothermal technique were dispersed in a chitosan/Pluronic F-127 solution (QO/Pl) to obtain a nanocomposite hybrid films. Nanoparticles and hybrid films were characterized by X-ray powder diffraction, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and alternating gradient magnetometry (AGM). Experimental results indicated that the BT:Co nanoparticles were encapsulated in the QO/Pl hybrid films and that the magnetic properties of the QO/Pl/BT:Co nanocomposites are similar to the naked BT:Co nanoparticles. Results indicate that Co doping produces an enhancement in the ferromagnetic behavior of the BT nanoparticle. The coating restricts this enhancement only to low-fields, leaving the diamagnetic behavior of BT at high-fields. Magnetically stable sizes (PSD) were obtained at 3% Co doping for both naked nanoparticles and hybrid films. These show an increased magnetic memory capacity and a softer magnetic hardness with respect to non-doped BT nanoparticles. - Highlights: • We described the synthesis of magnetic BaTiO 3 :Co dispersed in chitosan (QO)/Pluronic F-127 (Pl) solution by sonication to obtain nanocomposite hybrid films. • We describe the physical and magnetic properties of BaTiO 3 :Co nanoparticles and QO/Pl/BT:Co hybrid films. • The magnetic properties are defines by the presence of magnetic domains. These magnetic domains are close related with the amount of Co in the host lattice. • The prepared phases could be considered as multifunctional materials, with magnetic and ferri-electrical properties, with potential uses in the design of devices

  18. Complementary resistive switching in BaTiO3/NiO bilayer with opposite switching polarities

    Science.gov (United States)

    Li, Shuo; Wei, Xianhua; Lei, Yao; Yuan, Xincai; Zeng, Huizhong

    2016-12-01

    Resistive switching behaviors have been investigated in the Au/BaTiO3/NiO/Pt structure by stacking the two elements with different switching types. The conducting atomic force microscope measurements on BaTiO3 thin films and NiO thin films suggest that with the same active resistive switching region, the switching polarities in the two semiconductors are opposite to each other. It is in agreement with the bipolar hysteresis I-V curves with opposite switching polarities for single-layer devices. The bilayer devices show complementary resistive switching (CRS) without electroforming and unipolar resistive switching (URS) after electroforming. The coexistence of CRS and URS is mainly ascribed to the co-effect of electric field and Joule heating mechanisms, indicating that changeable of resistance in this device is dominated by the redistribution of oxygen vacancies in BaTiO3 and the formation, disruption, restoration of conducting filaments in NiO. CRS in bilayer with opposite switching polarities is effective to solve the sneak current without the introduction of any selector elements or an additional metal electrode.

  19. Deposition barium titanate (BaTiO3) doped lanthanum with chemical solution deposition

    International Nuclear Information System (INIS)

    Iriani, Y.; Nurhadi, N.; Jamaludin, A.

    2016-01-01

    Deposition of Barium Titanate (BaTiO 3 ) thin films used Chemical Solution Deposition (CSD) method and prepared with spin coater. BaTiO 3 is doped with lanthanum, 1%, 2%, and 3%. The thermal process use annealing temperature 900°C and holding time for 3 hours. The result of characterization with x-ray diffraction (XRD) equipment show that the addition of La 3+ doped on Barium Titanate caused the change of angle diffraction.The result of refine with GSAS software shows that lanthanum have been included in the structure of BaTiO 3 . Increasing mol dopant La 3+ cause lattice parameter and crystal volume become smaller. Characterization result using Scanning Electron Microscopy (SEM) equipment show that grain size (grain size) become smaller with increasing mole dopant (x) La 3+ . The result of characterization using Sawyer Tower methods show that all the samples (Barium Titanante and Barium Titanate doped lanthanum) are ferroelectric material. Increasing of mole dopant La 3+ cause smaller coercive field and remanent polarization increases. (paper)

  20. Luminescent Properties of Surface Functionalized BaTiO3 Embedded in Poly(methyl methacrylate)

    Science.gov (United States)

    Requena, Sebastian; Lacoul, Srijan; Strzhemechny, Yuri M.

    2014-01-01

    As-received BaTiO3 nanopowders of average grain sizes 50 nm and 100 nm were functionalized by (3-aminopropyl)triethoxysilane (APTES) and mixed with poly(methyl methacrylate)/toluene solution. The nanocomposite solution was spin coated on Si substrates to form thin films. The photoluminescence spectrum of the pure powder was composed of a bandgap emission at 3.0 eV and multiple bands centered about 2.5 eV. Surface functionalization of the BaTiO3 powder via APTES increases overall luminescence at room temperature while only enhancing bandgap emission at low-temperature. Polymer coating of the functionalized nanoparticles significantly enhances bandgap emissions while decreasing emissions associated with near-surface lattice distortions at 2.5 eV. PMID:28788468

  1. Luminescent Properties of Surface Functionalized BaTiO3 Embedded in Poly(methyl methacrylate

    Directory of Open Access Journals (Sweden)

    Sebastian Requena

    2014-01-01

    Full Text Available As-received BaTiO3 nanopowders of average grain sizes 50 nm and 100 nm were functionalized by (3-aminopropyltriethoxysilane (APTES and mixed with poly(methyl methacrylate/toluene solution. The nanocomposite solution was spin coated on Si substrates to form thin films. The photoluminescence spectrum of the pure powder was composed of a bandgap emission at 3.0 eV and multiple bands centered about 2.5 eV. Surface functionalization of the BaTiO3 powder via APTES increases overall luminescence at room temperature while only enhancing bandgap emission at low-temperature. Polymer coating of the functionalized nanoparticles significantly enhances bandgap emissions while decreasing emissions associated with near-surface lattice distortions at 2.5 eV.

  2. Dielectric enhancement of BaTiO3/SrTiO3 superlattices with embedded Ni nanocrystals

    International Nuclear Information System (INIS)

    Xiong Zhengwei; Sun Weiguo; Wang Xuemin; Jiang Fan; Wu Weidong

    2012-01-01

    Highlights: ► The BaTiO 3 /SrTiO 3 superlattices with embedded Ni NCs were successfully fabricated by L-MBE. ► The influence with the various concentrations of Ni nanocrystals embedded in BaTiO 3 /SrTiO 3 superlattices was also discussed. ► The BaTiO 3 /SrTiO 3 superlattices with lower concentration of embedded Ni NCs had higher permittivity and dielectric loss compared with the pure BaTiO 3 /SrTiO 3 superlattices. ► The dielectric enhancement of BaTiO 3 /SrTiO 3 superlattices with embedded Ni NCs was proposed to explained by Drude quasi-free-electron theory. - Abstract: The self-organized Ni nanocrystals (NCs) were embedded in BaTiO 3 /SrTiO 3 superlattices using laser molecular beam epitaxy (L-MBE). The stress of the composite films was increased with the increasing concentration of embedded Ni NCs, as investigation in stress calculation. The influence with the various concentrations of Ni NCs embedded in BaTiO 3 /SrTiO 3 superlattices was also discussed. The internal stress of the films was too strong to epitaxial growth of BaTiO 3 /SrTiO 3 superlattices. Compared with the pure BaTiO 3 /SrTiO 3 superlattices, the BaTiO 3 /SrTiO 3 superlattices with lower concentration of embedded Ni NCs had higher permittivity and dielectric loss. Furthermore, the dielectric enhancement of BaTiO 3 /SrTiO 3 superlattices with embedded Ni NCs was proposed to explained by Drude quasi-free-electron theory.

  3. Multiferroic properties of BiFeO3/BaTiO3 multilayered thin films

    International Nuclear Information System (INIS)

    Sharma, Savita; Tomar, Monika; Kumar, Ashok; Puri, Nitin K.; Gupta, Vinay

    2014-01-01

    Multilayered structures of multiferroic BiFeO 3 (BFO) and ferroelectric BaTiO 3 (BTO) have been fabricated using pulsed laser deposition (PLD). Ferromagnetic and ferroelectric properties of the multilayered system (BFO/BTO) have been investigated. It could be inferred that the magnetization increases with the incorporation of BTO buffer layer, which indicates a coupling between the ferroelectric and ferromagnetic orders. Vibrating sample magnetometer (VSM) measurements performed on the prepared multiferroic samples show that the magnetization is significantly increased (M s =56.88 emu/cm 3 ) for the multilayer system with more number of layers (four) keeping the total thickness of the multilayered system constant (350 nm) meanwhile maintaining the sufficiently enhanced ferroelectric properties (P r =29.68 µC/cm 2 )

  4. La-doped BaTiO3 heterostructures: Compensating the polarization discontinuity

    Directory of Open Access Journals (Sweden)

    D. P. Kumah

    2013-12-01

    Full Text Available We demonstrate a route to manipulate the polarization and internal electric field of a complex oxide heterostructure using a layering sequence based on the LaAlO3-SrTiO3 interface. By combining sensitive atomic-level mapping of the structure using direct x-ray phase-retrieval methods with theoretical modeling of the electrostatic charge and polarization, we have devised a novel single-domain polar heterostructure. We find that ionic rearrangement results in strain and free energy minimization, and eliminates the polarization discontinuity leading to a two-fold increase of the spontaneous polarization towards the surface of an ultra-thin single-domain BaTiO3 film.

  5. Microstructure and dielectric parameters of epitaxial SrRuO3/BaTiO3/SrRuO3 heterostructures

    Science.gov (United States)

    Boikov, Yu. A.; Claeson, T.

    2001-05-01

    Epitaxial films of ferroelectric barium titanate are desirable in a number of applications but their properties are inferior to those of bulk material. Relations between microstructure and dielectric properties may give better understanding of limitations. Trilayer heterostructures SrRuO3/BaTiO3/SrRuO3 were grown by laser ablation on (100)LaAlO3 and (100)MgO substrates. The BaTiO3 layer was granular in structure. When grown on (100)SrRuO3/(100)LaAlO3, it was preferentially a-axis oriented due to tensile mechanical stress. Using (100)MgO as a substrate, on the other hand, produced a mixture of about equal value of a-axis and c-axis oriented grains of BaTiO3. The dielectric permittivity, ɛ, of the BaTiO3 layer was almost twice as large, at T>200 K and f=100 kHz, for the LaAlO3 substrate as compared to the MgO one. Its maximum value (ɛ/ɛ0≈6200) depended on temperature of growth, grain size, and electric field and compares well with optimal values commonly used for ceramic material. The maximum in the ɛ(T) shifted from about 370 to 320 K when the grain size in the BaTiO3 film decreased from 100 to 40 nm. At T300 K, hysteresis loops in polarization versus electric field were roughly symmetric. The BaTiO3 films grown on (100)SrRuO3/(100)MgO exhibit the largest remnant polarizations and coercive fields in the temperature range 100-380 K.

  6. Direct detection of cysteine using functionalized BaTiO3 nanoparticles film based self-powered biosensor.

    Science.gov (United States)

    Selvarajan, Sophia; Alluri, Nagamalleswara Rao; Chandrasekhar, Arunkumar; Kim, Sang-Jae

    2017-05-15

    Simple, novel, and direct detection of clinically important biomolecules have continuous demand among scientific community as well as in market. Here, we report the first direct detection and facile fabrication of a cysteine-responsive, film-based, self-powered device. NH 2 functionalized BaTiO 3 nanoparticles (BT-NH 2 NPs) suspended in a three-dimensional matrix of an agarose (Ag) film, were used for cysteine detection. BaTiO 3 nanoparticles (BT NPs) semiconducting as well as piezoelectric properties were harnessed in this study. The changes in surface charge properties of the film with respect to cysteine concentrations were determined using a current-voltage (I-V) technique. The current response increased with cysteine concentration (linear concentration range=10µM-1mM). Based on the properties of the composite (BT/Ag), we created a self-powered cysteine sensor in which the output voltage from a piezoelectric nanogenerator was used to drive the sensor. The potential drop across the sensor was measured as a function of cysteine concentrations. Real-time analysis of sensor performance was carried out on urine samples by non-invasive method. This novel sensor demonstrated good selectivity, linear concentration range and detection limit of 10µM; acceptable for routine analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Flexoelectricity induced increase of critical thickness in epitaxial ferroelectric thin films

    International Nuclear Information System (INIS)

    Zhou Hao; Hong Jiawang; Zhang Yihui; Li Faxin; Pei Yongmao; Fang Daining

    2012-01-01

    Flexoelectricity describes the coupling between polarization and strain/stress gradients in insulating crystals. In this paper, using the Landau-Ginsburg-Devonshire phenomenological approach, we found that flexoelectricity could increase the theoretical critical thickness in epitaxial BaTiO 3 thin films, below which the switchable spontaneous polarization vanishes. This increase is remarkable in tensile films while trivial in compressive films due to the electrostriction caused decrease of potential barrier, which can be easily destroyed by the flexoelectricity, between the ferroelectric state and the paraelectric state in tensile films. In addition, the films are still in a uni-polar state even below the critical thickness due to the flexoelectric effect.

  8. Electric controlling of surface metal-insulator transition in the doped BaTiO3 film

    Directory of Open Access Journals (Sweden)

    Wei Xun

    2017-07-01

    Full Text Available Based on first-principles calculations, the BaTiO3(BTO film with local La-doping is studied. For a selected concentration and position of doping, the surface metal-insulator transition occurs under the applied electric field, and the domain appears near the surface for both bipolar states. Furthermore, for the insulated surface state, i.e., the downward polarization state in the doped film, the gradient bandgap structure is achieved, which favors the absorption of solar energy. Our investigation can provide an alternative avenue in modification of surface property and surface screening effect in polar materials.

  9. Spin-Coating and Characterization of Multiferroic MFe2O4 (M=Co, Ni) / BaTiO3 Bilayers

    Science.gov (United States)

    Quandt, Norman; Roth, Robert; Syrowatka, Frank; Steimecke, Matthias; Ebbinghaus, Stefan G.

    2016-01-01

    Bilayer films of MFe2O4 (M=Co, Ni) and BaTiO3 were prepared by spin coating of N,N-dimethylformamide/acetic acid solutions on platinum coated silicon wafers. Five coating steps were applied to get the desired thickness of 150 nm for both the ferrite and perovskite layer. XRD, IR and Raman spectroscopy revealed the formation of phase-pure ferrite spinels and BaTiO3. Smooth surfaces with roughnesses in the order of 3 to 5 nm were found in AFM investigations. Saturation magnetization of 347 emu cm-3 for the CoFe2O4/BaTiO3 and 188 emu cm-3 for the NiFe2O4/BaTiO3 bilayer, respectively were found. For the CoFe2O4/BaTiO3 bilayer a strong magnetic anisotropy was observed with coercivity fields of 5.1 kOe and 3.3 kOe (applied magnetic field perpendicular and parallel to film surface), while for the NiFe2O4/BaTiO3 bilayer this effect is less pronounced. Saturated polarization hysteresis loops prove the presence of ferroelectricity in both systems.

  10. Electro-Caloric Properties of BT/PZT Multilayer Thin Films Prepared by Sol-Gel Method.

    Science.gov (United States)

    Kwon, Min-Su; Lee, Sung-Gap; Kim, Kyeong-Min

    2018-09-01

    In this study, Barium Titanate (BT)/Lead Zirconate Titanate (PZT) multilayer thin films were fabricated by the spin-coating method on Pt (200 nm)/Ti (10 nm) SiO2 (100 nm)/P-Si (100) substrates using BaTiO3 and Pb(Zr0.90Ti0.10)O3 metal alkoxide solutions. The coating and heating procedure was repeated several times to form the multilayer thin films. All of BT/PZT multilayer thin films show X-ray diffraction patterns typical to a polycrystalline perovskite structure and a uniform and void free grain microstructure. The thickness of the BT and PZT film by one-cycle of drying/sintering was approximately 50 nm and all of the films consisted of fine grains with a flat surface morphology. The electrocaloric properties of BT/PZT thin films were investigated by indirect estimation. The results showed that the temperature change ΔT can be calculated as a function of temperature using Maxwell's relation; the temperature change reaches a maximum value of ~1.85 °C at 135 °C under an applied electric field of 260 kV/cm.

  11. Preparation and characterization of self-assembled percolative BaTiO3–CoFe2O4 nanocomposites via magnetron co-sputtering

    Directory of Open Access Journals (Sweden)

    Qian Yang

    2014-04-01

    Full Text Available BaTiO3–CoFe2O4 composite films were prepared on (100 SrTiO3 substrates by using a radio-frequency magnetron co-sputtering method at 750 °C. These films contained highly (001-oriented crystalline phases of perovskite BaTiO3 and spinel CoFe2O4, which can form a self-assembled nanostructure with BaTiO3 well-dispersed into CoFe2O4 under optimized sputtering conditions. A prominent dielectric percolation behavior was observed in the self-assembled nanocomposite. Compared with pure BaTiO3 films sputtered under similar conditions, the nanocomposite film showed higher dielectric constants and lower dielectric losses together with a dramatically suppressed frequency dispersion. This dielectric percolation phenomenon can be explained by the 'micro-capacitor' model, which was supported by measurement results of the electric polarization and leakage current.

  12. BaTiO3–P(VDF-HFP) nanocomposite dielectrics—Influence of surface modification and dispersion additives

    International Nuclear Information System (INIS)

    Ehrhardt, Claudia; Fettkenhauer, Christian; Glenneberg, Jens; Münchgesang, Wolfram; Pientschke, Christoph; Großmann, Thomas; Zenkner, Mandy; Wagner, Gerald; Leipner, Hartmut S.; Buchsteiner, Alexandra; Diestelhorst, Martin; Lemm, Sebastian; Beige, Horst; Ebbinghaus, Stefan G.

    2013-01-01

    Highlights: • Polymer composites were prepared using a sol–gel synthesized BaTiO 3 . • BaTiO 3 surface hydroxyle groups act as linkers for surfactant molecules. • The effect of chemical adjustment between surfactant and polymer host is studied. • A positive effect of an additional dispersant was found. • Dielectric properties of the resulting composite films are presented. -- Abstract: We report on BaTiO 3 –polymer composites as dielectrics for film capacitors. BaTiO 3 was synthesized by a sol–gel soft-chemistry method leading to spherical nanoparticles with a high degree of surface hydroxyl groups which turned out to be important for the bonding of surfactant molecules. As surfactants, n-octylphosphonic acid and 2,3,4,5,6-pentafluorobenzyl phosphonic acid were used to inhibit particle agglomeration and to improve the wetting behaviour with the polymer. The phosphonic acid-coated BaTiO 3 nanoparticles were dispersed in solutions of poly(vinylidefluoride-co-hexafluoropropylene). Composite films were prepared by the spin-coating technique. A systematic study was performed on the influence of varying oxide fractions, different surfactants and the effect of additional dispersion aids such as sodium dodecyl sulphate or BYK-W 9010 on the quality and dielectric properties of the films obtained. The chemical adjustment of the 2,3,4,5,6-pentaflourobenzyl phosphonic acid within the fluorinated organic host form a more uniform particle distribution and increase relative permittivity of the resulting composite material compared to the unflourinated surfactant. Additionally, an enhancement of the relative permittivity can be realized by adding of dispersants. These two components can increase the relative permittivity by factor 5 compared to the pure polymer material

  13. Morphology controlled ultrafine BaTiO3 based PVDF-HFP ...

    Indian Academy of Sciences (India)

    21

    ... for real applications. Kew Words: Polygonal, Barium Titanate, Hydrothermal, Dielectric and Sensor. 1. 2 ... structure and can be tuned further by substituting various dopants (Sr, Ca and Zr). .... Modified BaTiO3 induces less displacement of Ti and O ions along c- axis and .... sputter coated on both sides with gold. The films ...

  14. Thickness dependent charge transport in ferroelectric BaTiO3 heterojunctions

    Science.gov (United States)

    Singh, Pooja; Rout, P. K.; Singh, Manju; Rakshit, R. K.; Dogra, Anjana

    2015-09-01

    We have investigated the effect of ferroelectric barium titanate (BaTiO3) film thickness on the charge transport mechanism in pulsed laser deposited epitaxial metal-ferroelectric semiconductor junctions. The current (I)-voltage (V) measurements across the junctions comprising of 20-500 nm thick BaTiO3 and conducting bottom electrode (Nb: SrTiO3 substrate or La2/3Ca1/3MnO3 buffer layer) demonstrate the space charge limited conduction. Further analysis indicates a reduction in the ratio of free to trapped carriers with increasing thickness in spite of decreasing trap density. Such behaviour arises the deepening of the shallow trap levels (I-V curves implies a bipolar resistive switching behaviour, which can be explained in terms of charge trapping and de-trapping process.

  15. Aerosol Combustion Synthesis of Nanopowders and Processing to Functional Thin Films

    Science.gov (United States)

    Yi, Eongyu

    In this dissertation, the advantages of liquid-feed flame spray pyrolysis (LF-FSP) process in producing nanoparticles (NPs) as well as processing the produced NPs to ceramic/polymer nanocomposite films and high density polycrystalline ceramic films are demonstrated. The LF-FSP process aerosolizes alcohol solutions of metalloorganic precursors by oxygen and combusts them at > 1500 °C. The combustion products are rapidly quenched ( 10s of ms) to green and potentially lower cost alternative. We then show the versatility of NPs in formulating flexible ceramic/polymer nanocomposites (BaTiO3/epoxy) with superior properties. Volume fractions of the BaTiO3 filler and composite film thicknesses were controlled to adjust the net dielectric constant and the capacitance. Measured net dielectric constants further deviated from theory, with increasing solids loadings, due to NP agglomeration. Wound nanocomposite capacitors showed ten times higher capacitance compared to the commercial counterpart. Following series of studies explore the use of flame made NPs in processing Li+ conducting membranes. Systematic doping studies were conducted in the LiTi2(PO4)3 system to modify the lattice constant, conduction channel width, and sintering behavior by introducing Al3+ and Si4+ dopants. Excess Li2O content was also adjusted to observe its effect on final microstructures and phase compositions. Improved densification rates were found in Li1.7 Al0.3Ti1.7Si0.4P2.6O 12 composition and thin films (52+/-1 microm) with conductivities of 0.3-0.5 mS cm-1 were achieved. Li6.25M0.25La3Zr2O12 (M = Al3+, Ga3+) thin films (25-28 microm) with conductivities of 0.2-1.3 mS cm-1 were also successfully processed using flame made NPs, overcoming processing challenges extant, resulting in significantly reduced energy input required for densification. Heating schedules, sintering atmospheres, and types of substrates were controlled to observe their effect on the sintering behavior. Furthermore, green film

  16. Fabrication of Crack-Free Barium Titanate Thin Film with High Dielectric Constant Using Sub-Micrometric Scale Layer-by-Layer E-Jet Deposition

    Directory of Open Access Journals (Sweden)

    Junsheng Liang

    2016-01-01

    Full Text Available Dense and crack-free barium titanate (BaTiO3, BTO thin films with a thickness of less than 4 μm were prepared by using sub-micrometric scale, layer-by-layer electrohydrodynamic jet (E-jet deposition of the suspension ink which is composed of BTO nanopowder and BTO sol. Impacts of the jet height and line-to-line pitch of the deposition on the micro-structure of BTO thin films were investigated. Results show that crack-free BTO thin films can be prepared with 4 mm jet height and 300 μm line-to-line pitch in this work. Dielectric constant of the prepared BTO thin film was recorded as high as 2940 at 1 kHz at room temperature. Meanwhile, low dissipation factor of the BTO thin film of about 8.6% at 1 kHz was also obtained. The layer-by-layer E-jet deposition technique developed in this work has been proved to be a cost-effective, flexible and easy to control approach for the preparation of high-quality solid thin film.

  17. Vacancy-induced magnetism in BaTiO3(001) thin films based on density functional theory.

    Science.gov (United States)

    Cao, Dan; Cai, Meng-Qiu; Hu, Wang-Yu; Yu, Ping; Huang, Hai-Tao

    2011-03-14

    The origin of magnetism induced by vacancies on BaTiO(3)(001) surfaces is investigated systematically by first-principles calculations within density-functional theory. The calculated results show that O vacancy is responsible for the magnetism of the BaO-terminated surface and the magnetism of the TiO(2)-terminated surface is induced by Ti vacancy. For the BaO-terminated surface, the magnetism mainly arises from the unpaired electrons that are localized in the O vacancy basin. In contrast, for the TiO(2)-terminated surface, the magnetism mainly originates from the partially occupied O-2p states of the first nearest neighbor O atoms surrounding the Ti vacancy. These results suggest the possibility of implementing magneto-electric coupling in conventional ferroelectric materials.

  18. Chemical bath deposition of Cu{sub 3}BiS{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Deshmukh, S.G., E-mail: deshmukhpradyumn@gmail.com; Vipul, Kheraj, E-mail: vipulkheraj@gmail.com [Department of Applied Physics, Sardar Vallabhbhai National Institute of Technology, Ichchhanath, Surat (India); Panchal, A.K. [Department of Electrical Engineering, Sardar Vallabhbhai National Institute of Technology, Ichchhanath, Surat (India)

    2016-05-06

    First time, copper bismuth sulfide (Cu{sub 3}BiS{sub 3}) thin films were synthesized on the glass substrate using simple, low-cost chemical bath deposition (CBD) technique. The synthesized parameters such as temperature of bath, pH and concentration of precursors were optimized for the deposition of uniform, well adherent Cu{sub 3}BiS{sub 3} thin films. The optical, surface morphology and structural properties of the Cu{sub 3}BiS{sub 3} thin films were studied using UV-VIS-NIR spectra, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The as- synthesized Cu{sub 3}BiS{sub 3} film exhibits a direct band gap 1.56 to 1.58 eV having absorption coefficient of the order of 10{sup 5} cm{sup −1}. The XRD declares the amorphous nature of the films. SEM images shows films were composed of close-packed fine spherical nanoparticles of 70-80 nm in diameter. The chemical composition of the film was almost stoichiometric. The optical study indicates that the Cu{sub 3}BiS{sub 3} films can be applied as an absorber layer for thin film solar cells.

  19. Influence of applied electric field annealing on the microwave properties of (Ba0.5Sr0.5)TiO3 thin films

    Science.gov (United States)

    Cho, Kwang-Hwan; Lee, Chil-Hyoung; Kang, Chong-Yun; Yoon, Seok-Jin; Lee, Young-Pak

    2007-04-01

    The effect of heat treatment in electric field on the structure and dielectric properties at microwave range of rf magnetron sputtering derived (Ba0.5Sr0.5)TiO3 thin films have been studied. It has been demonstrated that postannealing in the proper electric field can increase the dielectric constant and the tunability. The increased out-of-plane lattice constant in the electric-annealed films indicated the formation of small polar regions with tetragonal structure, which are responsible for the increased dielectric constant and tunability. It was proposed that the segregation of Ti3+ ions caused by electric annealing could induce the formation of BaTiO3-like regions, which are ferroelectric at room temperature. And in dielectric loss, as the Ti-O bonding lengths increase, the energy scattering on the ferroelectric mode also increases. So, the value of dielectric loss is slightly increased.

  20. Electrochromic properties of nanocrystalline MoO3 thin films

    International Nuclear Information System (INIS)

    Hsu, C.-S.; Chan, C.-C.; Huang, H.-T.; Peng, C.-H.; Hsu, W.-C.

    2008-01-01

    Electrochromic MoO 3 thin films were prepared by a sol-gel spin-coating technique. The spin-coated films were initially amorphous; they were calcined, producing nanocrystalline MoO 3 thin films. The effects of annealing temperatures ranging from 100 o C to 500 o C were investigated. The electrochemical and electrochromic properties of the films were measured by cyclic voltammetry and by in-situ optical transmittance techniques in 1 M LiClO 4 /propylene carbonate electrolyte. Experimental results showed that the transmittance of MoO 3 thin films heat-treated at 350 o C varied from 80% to 35% at λ = 550 nm (ΔT = ∼ 45%) and from 86% to 21% at λ ≥ 700 nm (ΔT = ∼ 65%) after coloration. Films heat-treated at 350 deg. C exhibited the best electrochromic properties in the present study

  1. Synthesis and characterization of BaTiO3 ferroelectric material

    International Nuclear Information System (INIS)

    Osman, K.I.

    2011-01-01

    BaTiO 3 powder was prepared at low temperatures using the solid-state reaction, starting with two different precursors; the BaCO 3 /TiO 2 and the Ba(NO 3 ) 2 /TiO 2 powder mixtures. It was found that, a single phase BaTiO 3 was formed after calcination at 750 degree C for 10 h and at 600 degree C for 6 h for the first and second mixtures, respectively. Thermal and XRD analyses were used to study the formation kinetics of BaTiO 3 . Contracting volume reaction model was found to control both reactions. The SEM of the as milled powder, TMA, TG and thermodynamics analysis have been used to propose a realistic approach describing the reaction mechanism of BaTiO 3 . Characterization and the dielectric properties of the sintered BaTiO 3 were investigated. The relative permittivity and the dielectric loss measured at room temperature and at 1 khz were 2028.5 and 0.043 for BaTiO 3 prepared from BaCO 3 /TiO 2 , while they were 1805.33 and 0.41 for BaTiO 3 prepared from Ba(NO 3 ) 2 /TiO 2 .

  2. Wet routes of high purity BaTiO3 nanopowders

    International Nuclear Information System (INIS)

    Wang Liqiu; Liu Liang; Xue Dongfeng; Kang Hongmin; Liu Changhou

    2007-01-01

    High purity BaTiO 3 nanopowders were prepared in wet routes through stearic acid gel (SAG) and acetic acid gel (AAG) techniques, respectively. BaTiO 3 samples were characterized by X-ray diffraction, transmission electron microscope, Fourier transform infrared spectrometry, X-ray fluorescence spectrometry, and thermal gravimetric analysis. The present results indicate that both methods have a similar reaction process during calcination, while BaTiO 3 crystallites were initially formed at 550 deg. C by SAG and 800 deg. C by AAG. Both methods could produce BaTiO 3 powders with a cubic perovskite structure, while they had different grain size distributions within 25-50 nm for SAG and 50-80 nm for AAG. BaTiO 3 samples prepared by SAG had a lower agglomeration than those by AAG. SAG has shown many distinctive advantages in the preparation of high purity BaTiO 3 nanopowders, without Ba and Ti losses and hazardous wastes

  3. Effect of Zn-doping on the structural and optical properties of BaTiO3 thin films grown by pulsed laser deposition

    International Nuclear Information System (INIS)

    Fasasi, A.Y.; Maaza, M.; Rohwer, E.G.; Knoessen, D.; Theron, Ch.; Leitch, A.; Buttner, U.

    2008-01-01

    Thin films of zinc oxide doped barium titanate (BaZn x Ti 1-x O 3 ) have been prepared by pulsed laser ablation using different targets having zinc composition varying between x = 1 to 5 wt.% at a step of 1 wt.% on corning glass microscope slide and silicon substrates. X-ray diffraction analyses showed films to be of tetragonal phase with an average grain size of 20 nm and c/a ratio of 1.08 indicating lattice expansion due to ZnO incorporation. Atomic force microscopy studies of the prepared thin films indicated smooth surfaces with average roughness of 1.84 and 4.6 nm for as-deposited and sintered specimens respectively. Scanning electron microscopy showed films to be smooth and uniform. UV-Visible as well as Fourier Transform Infrared transmission measurements showed a transmission of more than 80% in the visible and 5-20% in the near infrared. The transmittance is strongly affected by annealing. There is a dependence of band gap energy on film thickness as well as on the amount of ZnO added. High ZnO dopant level led to an increase in the band gap

  4. Effects of crystallization on structural and dielectric properties of thin amorphous films of (1 - x)BaTiO3-xSrTiO3 (x=0-0.5, 1.0)

    Science.gov (United States)

    Kawano, H.; Morii, K.; Nakayama, Y.

    1993-05-01

    The possibilities for fabricating solid solutions of (Ba1-x,Srx)TiO3 (x≤0.5,1.0) by crystallization of amorphous films and for improving their dielectric properties by adjusting the Sr content were investigated. Thin amorphous films were prepared from powder targets consisting of mixtures of BaTiO3 and SrTiO3 by sputtering with a neutralized Ar-ion beam. The amorphous films crystallized into (Ba1-x, Srx)TiO3 solid solutions with a cubic perovskite-type structure after annealing in air at 923 K for more than 1 h. The Debye-type dielectric relaxation was observed for the amorphous films, whereas the crystallized films showed paraelectric behavior. The relative dielectric constants were of the order of 20 for the amorphous samples, but increased greatly after crystallization to about 60-200, depending on the composition; a larger increase in the dielectric constant was observed in the higher Sr content films, in the range x≤0.5, which could be correlated with an increase in the grain size of the crystallites. The crystallization processes responsible for the difference in the grain size are discussed based on the microstructural observations.

  5. PLD prepared bioactive BaTiO.sub.3./sub. films on TiNb implants

    Czech Academy of Sciences Publication Activity Database

    Jelínek, Miroslav; Vaněk, Přemysl; Tolde, Z.; Buixaderas, Elena; Kocourek, Tomáš; Studnička, Václav; Drahokoupil, Jan; Petzelt, Jan; Remsa, Jan; Tyunina, Marina

    2017-01-01

    Roč. 70, Jan (2017), s. 334-339 ISSN 0928-4931 R&D Projects: GA ČR(CZ) GA15-05864S; GA ČR(CZ) GA15-01558S Institutional support: RVO:68378271 Keywords : BaTiO 3 * thin films * pld * implants * TiNb * ferroelectricity Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.)

  6. Strain and electric field mediated manipulation of magnetism in La_(_1_-_x_)Sr_xMnO_3/BaTiO_3 heterostructures

    International Nuclear Information System (INIS)

    Schmitz, Markus

    2016-01-01

    Heterostructures of ferromagnetic La_1_-_xSr_xMnO_3 (LSMO) and ferroelectric BaTiO_3 (BTO) were produced and investigated for their structural and magnetic properties. The combination of these ferroic properties can lead to an artificial multiferroic. Special emphasis was given to the manipulation of magnetic properties by applying electric fields. A magneto-electric coupling could be observed in the heterostructures under investigation. Epitaxial LSMO thin films were grown on BTO substrates using a state-of-the-art oxide molecular beam epitaxy (OMBE) and a high oxygen sputtering system (HOPSS). Stoichiometric La_1_-_xSr_xMnO_3 films with doping levels of x=0.5 and x=0.3 were produced. The film quality in terms of roughness and crystalline structure was confirmed by X-ray scattering methods. The presence of structural domains in the BaTiO_3 single crystal substrate, whose proportion could be altered due to the application of electric fields, was shown by X-ray diffraction. Tensile strain is induced into the epitaxial La_1_-_xSr_xMnO_3 films in the whole temperature range under investigation. The magnetization of LSMO alteres by the variation of strain induced into the film, generated by the different structural phases of single crystal BaTiO_3 substrates. The magnetization shows sharp steps at the structural phase transition temperatures of BTO. The evaluation of magnetic hysteresis loops reveals a change of the magnetic anisotropy of LSMO for each structural phase of BTO, but also within the orthorhombic phase. Special focus was given to the manipulation of magnetic properties by the application of electric fields. A newly established measurement option was used to determine the magnetic response to an applied electric field as a function of temperature and magnetic field. The electrically induced modification of the magnetization is profound near the structural phase transition temperatures. Electrical hysteresis loops give a detailed view on the influence of the

  7. Symmetry, strain, defects, and the nonlinear optical response of crystalline BaTiO3/silicon

    Science.gov (United States)

    Kormondy, Kristy; Abel, Stefan; Popoff, Youri; Sousa, Marilyne; Caimi, Daniele; Siegwart, Heinz; Marchiori, Chiara; Rossell, Marta; Demkov, Alex; Fompeyrine, Jean

    Recent progress has been made towards exploiting the linear electro-optic or Pockels effect in ferroelectric BaTiO3 (BTO) for novel integrated silicon photonics devices. In such structures, the crystalline symmetry and domain structure of BTO determine which electro-optic tensor elements are accessible under application of an external electric field. For epitaxial thin films of BTO on Si (001), the role of defects in strain relaxation can lead to very different crystalline symmetry even for films of identical thickness. Indeed, through geometric phase analysis of high-resolution scanning transmission electron microscopy images, we map changes of the in-plane and out-of-plane lattice parameters across two 80-nm-thick BTO films. A corresponding 20% difference in the effective electro-optic response was measured by analyzing induced rotation of the polarization of a laser beam (λ = 1550 nm) transmitted through lithographically defined electrodes. Understanding, controlling, and modelling the role of BTO symmetry in nonlinear optics is of fundamental importance for the development of a hybrid BTO/Si photonics platform.. Work supported by the NSF (IRES-1358111), AFOSR (FA9550-12-10494), and European Commission (FP7-ICT-2013-11-619456-SITOGA).

  8. Electrochemical Behavior of TiO2 Nanoparticle Doped WO3 Thin Films

    Directory of Open Access Journals (Sweden)

    Suvarna R. Bathe

    2014-01-01

    Full Text Available Nanoparticle TiO2 doped WO3 thin films by pulsed spray pyrolysis technique have been studied on fluorine tin doped (FTO and glass substrate. XRD shows amorphous nature for undoped and anatase phase of TiO2 having (101 plane for nanoparticle TiO2 doped WO3 thin film. SEM shows microfibrous reticulated porous network for WO3 with 600 nm fiber diameter and nanocrystalline having size 40 nm for TiO2 nanoparticle doped WO3 thin film. TiO2 nanoparticle doped WO3 thin film shows ~95% reversibility due to may be attributed to nanocrystalline nature of the film, which helpful for charge insertion and deinsertion process. The diffusion coefficient for TiO2 nanoparticle doped WO3 film is less than undoped WO3.

  9. Chemically deposited Sb2S3 thin films for optical recording

    International Nuclear Information System (INIS)

    Shaji, S; Arato, A; Castillo, G Alan; Palma, M I Mendivil; Roy, T K Das; Krishnan, B; O'Brien, J J; Liu, J

    2010-01-01

    Laser induced changes in the properties of Sb 2 S 3 thin films prepared by chemical bath deposition are described in this paper. Sb 2 S 3 thin films of thickness 550 nm were deposited from a solution containing SbCl 3 and Na 2 S 2 O 3 at 27 0 C for 5 h. These thin films were irradiated by a 532 nm continuous wave laser beam under different conditions at ambient atmosphere. X-ray diffraction analysis showed amorphous to polycrystalline transformation due to laser exposure of these thin films. Morphology and composition of these films were described. Optical properties of these films before and after laser irradiation were analysed. The optical band gap of the material was decreased due to laser induced crystallization. The results obtained confirm that there is further scope for developing this material as an optical recording media.

  10. Temperature-dependent leakage current behavior of epitaxial Bi0.5Na0.5TiO3-based thin films made by pulsed laser deposition

    Science.gov (United States)

    Hejazi, M. M.; Safari, A.

    2011-11-01

    This paper discusses the electrical conduction mechanisms in a 0.88 Bi0.5Na0.5TiO3-0.08 Bi0.5K0.5TiO3-0.04 BaTiO3 thin film in the temperature range of 200-350 K. The film was deposited on a SrRuO3/SrTiO3 substrate by pulsed laser deposition technique. At all measurement temperatures, the leakage current behavior of the film matched well with the Lampert's triangle bounded by three straight lines of different slopes. The relative location of the triangle sides varied with temperature due to its effect on the density of charge carriers and un-filled traps. At low electric fields, the ohmic conduction governed the leakage mechanism. The calculated activation energy of the trap is 0.19 eV implying the presence of shallow traps in the film. With increasing the applied field, an abrupt increase in the leakage current was observed. This was attributed to a trap-filling process by the injected carriers. At sufficiently high electric fields, the leakage current obeyed the Child's trap-free square law suggesting the space charge limited current was the dominant mechanism.

  11. Optical properties of WO3 thin films using surface plasmon resonance technique

    International Nuclear Information System (INIS)

    Paliwal, Ayushi; Sharma, Anjali; Gupta, Vinay; Tomar, Monika

    2014-01-01

    Indigenously assembled surface plasmon resonance (SPR) technique has been exploited to study the thickness dependent dielectric properties of WO 3 thin films. WO 3 thin films (80 nm to 200 nm) have been deposited onto gold (Au) coated glass prism by sputtering technique. The structural, optical properties and surface morphology of the deposited WO 3 thin films were studied using X-ray diffraction, UV-visible spectrophotometer, Raman spectroscopy, and Scanning electron microscopy (SEM). XRD analysis shows that all the deposited WO 3 thin films are exhibiting preferred (020) orientation and Raman data indicates that the films possess single phase monoclinic structure. SEM images reveal the variation in grain size with increase in thickness. The SPR reflectance curves of the WO 3 /Au/prism structure were utilized to estimate the dielectric properties of WO 3 thin films at optical frequency (λ = 633 nm). As the thickness of WO 3 thin film increases from 80 nm to 200 nm, the dielectric constant is seen to be decreasing from 5.76 to 3.42, while the dielectric loss reduces from 0.098 to 0.01. The estimated value of refractive index of WO 3 film is in agreement to that obtained from UV-visible spectroscopy studies. The strong dispersion in refractive index is observed with wavelength of incident laser light

  12. Optical constants of CH3NH3PbBr3 perovskite thin films measured by spectroscopic ellipsometry

    KAUST Repository

    Alias, Mohd Sharizal

    2016-07-14

    The lack of optical constants information for hybrid perovskite of CH3NH3PbBr3 in thin films form can delay the progress of efficient LED or laser demonstration. Here, we report on the optical constants (complex refractive index and dielectric function) of CH3NH3PbBr3 perovskite thin films using spectroscopic ellipsometry. Due to the existence of voids, the refractive index of the thin films is around 8% less than the single crystals counterpart. The energy bandgap is around 2.309 eV as obtained from photoluminescence and spectrophotometry spectra, and calculated from the SE analysis. The precise measurement of optical constants will be useful in designing optical devices using CH3NH3PbBr3 thin films.

  13. Enhanced electrochromic coloration in Ag nanoparticle decorated WO3 thin films

    International Nuclear Information System (INIS)

    Kharade, Rohini R.; Mali, Sawanta S.; Patil, Satish P.; Patil, Kashinath R.; Gang, Myong G.; Patil, Pramod S.; Kim, Jin H.; Bhosale, Popatrao N.

    2013-01-01

    Highlights: • Electrochromic WO 3 /Ag nanocomposites prepared by hybrid physico-chemical route. • XRD and XPS results confirm formation of Ag 8 W 4 O 16 phase. • WO 3 /Ag thin films showed good optical transmittance change and coloration efficiency. • SPR enhanced coloration and bleaching mechanism is well explained for electrochromism. • Color stimuli are quantified using CIE chromaticity principles. -- Abstract: WO 3 /Ag composite thin films were prepared by microwave assisted sol–gel synthesis (MW-SGS) of WO 3 followed by vacuum evaporation of Ag nanoparticles and their enhanced electrochromic coloration was investigated. The composition and morphology of WO 3 thin films with different thickness of Ag layer obtained by vacuum evaporation were investigated. Distinct plasmon absorption bands of Ag nanoparticle thin films were obtained. The optical band gap energy of WO 3 /Ag films decreased with increasing the Ag layer thickness. The surface of these films has been examined using X-ray photoelectron spectroscopy (XPS) to gain information about the chemical states of species present at surfaces. Experimental results indicated that the conductivity of the films increased after surface modification by Ag layer. To investigate the origin of enhanced electrochromic absorption in optical properties, working electrode consisting of WO 3 /Ag thin film was used and observed the optical properties during electrochemical reaction. It was found that composite electrode shows enhancement in electrochromic properties in terms of optical modulation (ΔOD) and coloration efficiency (η)

  14. Metal-insulator transition induced in CaVO3 thin films

    International Nuclear Information System (INIS)

    Gu Man; Laverock, Jude; Chen, Bo; Smith, Kevin E.; Wolf, Stuart A.; Lu Jiwei

    2013-01-01

    Stoichiometric CaVO 3 (CVO) thin films of various thicknesses were grown on single crystal SrTiO 3 (STO) (001) substrates using a pulsed electron-beam deposition technique. The CVO films were capped with a 2.5 nm STO layer. We observed a temperature driven metal-insulator transition (MIT) in CVO films with thicknesses below 4 nm that was not observed in either thick CVO films or STO films. The emergence of this MIT can be attributed to the reduction in effective bandwidth due to a crossover from a three-dimensional metal to a two-dimensional insulator. The insulating phase was only induced with a drive current below 0.1 μA. X-ray absorption measurements indicated different electronic structures for thick and very thin films of CVO. Compared with the thick film (∼60 nm), thin films of CVO (2–4 nm) were more two-dimensional with the V charge state closer to V 4+ .

  15. Effect of Sr doping on LaTiO3 thin films

    International Nuclear Information System (INIS)

    Vilquin, B.; Kanki, T.; Yanagida, T.; Tanaka, H.; Kawai, T.

    2005-01-01

    We report on the electric properties of La 1-x Sr x TiO 3 (0 ≤ x ≤ 0.5) thin films fabricated by pulsed laser deposition method. Crystallographic measurement of the thin films showed the epitaxial c-axis perovskite structure. The electric property of LaTiO 3 thin film, which is a typical Mott insulative material in bulk, showed insulative behaviour, while the Sr-doped films showed metallic conduction suffering electron-electron scattering. Below x = 0.1, the major carrier type was identified to be hole, and switched to electron with further increasing Sr-doping above x = 0.15. In fact, the switching from p-type to n-type for La 1-x Sr x TiO 3 thin films is first demonstrated in this study. The transition suggests that effective Coulomb gap vanishes due to over-additional Sr doping

  16. Low temperature dielectric relaxation and charged defects in ferroelectric thin films

    Directory of Open Access Journals (Sweden)

    A. Artemenko

    2013-04-01

    Full Text Available We report a dielectric relaxation in BaTiO3-based ferroelectric thin films of different composition and with several growth modes: sputtering (with and without magnetron and sol-gel. The relaxation was observed at cryogenic temperatures (T < 100 K for frequencies from 100 Hz up to 10 MHz. This relaxation activation energy is always lower than 200 meV and is very similar to the relaxation that we reported in the parent bulk perovskites. Based on our Electron Paramagnetic Resonance (EPR investigation, we ascribe this dielectric relaxation to the hopping of electrons among Ti3+-V(O charged defects. Being dependent on the growth process and on the amount of oxygen vacancies, this relaxation can be a useful probe of defects in actual integrated capacitors with no need for specific shaping.

  17. Fabrication and Film Qualification of Sr Modified Pb(Ca) TiO3 Thin Films

    International Nuclear Information System (INIS)

    Naw Hla Myat San; Khin Aye Thwe; Than Than Win; Yin Maung Maung; Ko Ko Kyaw Soe

    2011-12-01

    Strontium and calcium - modified lead titanate (Pb0.7 Ca0.15 Sr0.15 ) TiO3 (PCST)thin films were prepared by using spin coating technique. Phase transition of PCST was interpreted by means of Er-T characteristics. Process temperature dependence on micro-structure of PCST film was studied. Charge conduction mechanism of PCST thin film was also investigated for film qualification.

  18. Achieving 3-D Nanoparticle Assembly in Nanocomposite Thin Films via Kinetic Control

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jingyu; Xiao, Yihan; Xu, Ting [UCB

    2017-02-20

    Nanocomposite thin films containing well-ordered nanoparticle (NP) assemblies are ideal candidates for the fabrication of metamaterials. Achieving 3-D assembly of NPs in nanocomposite thin films is thermodynamically challenging as the particle size gets similar to that of a single polymer chain. The entropic penalties of polymeric matrix upon NP incorporation leads to NP aggregation on the film surface or within the defects in the film. Controlling the kinetic pathways of assembly process provides an alternative path forward by arresting the system in nonequilibrium states. Here, we report the thin film 3-D hierarchical assembly of 20 nm NPs in supramolecules with a 30 nm periodicity. By mediating the NP diffusion kinetics in the supramolecular matrix, surface aggregation of NPs was suppressed and NPs coassemble with supramolecules to form new 3-D morphologies in thin films. The present studies opened a viable route to achieve designer functional composite thin films via kinetic control.

  19. X-ray-induced thinning of 3He and 3He/4He mixture films

    International Nuclear Information System (INIS)

    Penanen, Konstantin; Fukuto, Masafumi; Silvera, Isaac F.; Pershan, Peter

    2000-01-01

    Films of isotopic mixtures of helium have been studied using x-ray specular reflectivity techniques. In contrast with superfluid 4 He films, x-ray exposure causes a reduction in the thickness of 4 He films above the superfluid transition as well as films of pure 3 He and 3 He/ 4 He mixtures. One proposed model that could account for this effect is a charging model, in which thinning is caused by electrostatic pressure of free charges that accumulate on the helium surface. Unfortunately, this model is not fully consistent with all of the experimental observations. A localized heating model, in which indirect heating of the film causes it to thin would explain the data if there were dissipative film flow in the 3 He/ 4 He mixtures at temperatures where the bulk is superfluid. We argue that various published experimental results suggest such an effect. In this model, film thinning data for dilute 3 He/ 4 He films indicates dissipation that is linear in 3 He content of the film over two orders of magnitude

  20. Optical properties of the c-axis oriented LiNbO3 thin film

    International Nuclear Information System (INIS)

    Shandilya, Swati; Sharma, Anjali; Tomar, Monika; Gupta, Vinay

    2012-01-01

    C-axis oriented Lithium Niobate (LiNbO 3 ) thin films have been deposited onto epitaxially matched (001) sapphire substrate using pulsed laser deposition technique. Structural and optical properties of the thin films have been studied using the X-ray diffraction (XRD) and UV–Visible spectroscopy respectively. Raman spectroscopy has been used to study the optical phonon modes and defects in the c-axis oriented LiNbO 3 thin films. XRD analysis indicates the presence of stress in the as-grown LiNbO 3 thin films and is attributed to the small lattice mismatch between LiNbO 3 and sapphire. Refractive index (n = 2.13 at 640 nm) of the (006) LiNbO 3 thin films was found to be slightly lower from the corresponding bulk value (n = 2.28). Various factors responsible for the deviation in the refractive index of (006) LiNbO 3 thin films from the corresponding bulk value are discussed and the deviation is mainly attributed to the lattice contraction due to the presence of stress in deposited film.

  1. Review of WO3 thin film preparation for photoelectrochemical water splitting

    International Nuclear Information System (INIS)

    Ehsan Eftekhari; Mohammad Kassim

    2009-01-01

    Full text: Tungsten trioxide (WO 3 ), which is one of the most essential materials in our daily life has appeared as an excellent photo electrode material for environmental purification. The nano-size of WO 3 thin film water-splitting technology has great potential for environmentally friendly solar-hydrogen production for the future hydrogen economy. There are several methods for producing tungsten oxide film. In this review, we outlined several WO 3 thin film preparation methods such as doctor Bladding, sputtering, layer-by-layer brush painting, spray pyrolysis deposition, sol-gel and other methods. Here we compare the maximum photocurrent obtained, different condition for preparation of WO 3 thin film and characterization outcome. (author)

  2. Studies of electronic and magnetic properties of LaVO3 thin film

    Science.gov (United States)

    Jana, Anupam; Karwal, Sharad; Choudhary, R. J.; Phase, D. M.

    2018-04-01

    We have investigated the electronic and magnetic properties of pulsed laser deposited Mott insulator LaVO3 (LVO) thin film. Structural characterization revels the single phase [00l] oriented LVO thin film. Enhancement of out of plane lattice parameter indicates the compressively strained LVO film. Electron spectroscopic studies demonstrate that vanadium is present in V3+ state. An energy dispersive X-ray spectroscopic study ensures the stoichiometric growth of the film. Very smooth surface is observed in scanning electron micrograph. Colour mapping for elemental distribution reflect the homogeneity of LVO film. The bifurcation between zero-field-cooled and Field-cooled curves clearly points towards the weak ferromagnetic phase presence in compressively strained LVO thin film. A finite value of coercivity at 300 K reflects the possibility of room temperature ferromagnetism of LVO thin film.

  3. Properties of MoO3 thin film polymorphs

    International Nuclear Information System (INIS)

    McCarron, E.M.; Carcia, P.F.

    1987-01-01

    Thin film polymorphs of molybdenum trioxide have been synthesized by RF sputtering. Films deposited on thermally floating substrates are polycrystalline and exhibit preferred orientation. Depending upon the oxygen partial pressure maintained during sputtering, the films can be made to crystallize in either the thermodynamically stable orthorhombic α MoO 3 form (unique 2D-layered structure) or the metastable monoclinic β MoO 3 phase (3D ReO 3 -related structure). Metastable β films can be converted thermally to the α phase and the transformation appears topotactic. Films deposited on the cooled substrates are amorphous. A correlation between the particular phase formed and adatom mobility is noted

  4. Strain Induced Magnetism in SrRuO3 Epitaxial Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Grutter, A.; Wong, F.; Arenholz, E.; Liberati, M.; Suzuki, Y.

    2010-01-10

    Epitaxial SrRuO{sub 3} thin films were grown on SrTiO{sub 3}, (LaAlO{sub 3}){sub 0.3}(SrAlO{sub 3}){sub 0.7} and LaAlO{sub 3} substrates inducing different biaxial compressive strains. Coherently strained SrRuO{sub 3} films exhibit enhanced magnetization compared to previously reported bulk and thin film values of 1.1-1.6 {micro}{sub B} per formula unit. A comparison of (001) and (110) SrRuO{sub 3} films on each substrate indicates that films on (110) oriented have consistently higher saturated moments than corresponding (001) films. These observations indicate the importance of lattice distortions in controlling the magnetic ground state in this transitional metal oxide.

  5. Extending the 3ω method: thermal conductivity characterization of thin films.

    Science.gov (United States)

    Bodenschatz, Nico; Liemert, André; Schnurr, Sebastian; Wiedwald, Ulf; Ziemann, Paul

    2013-08-01

    A lock-in technique for measurement of thermal conductivity and volumetric heat capacity of thin films is presented. The technique is based on the 3ω approach using electrical generation and detection of oscillatory heat along a thin metal strip. Thin films are deposited onto the backside of commercial silicon nitride membranes, forming a bilayer geometry with distinct thermal parameters. Stepwise comparison to an adapted heat diffusion model delivers these parameters for both layers. Highest sensitivity is found for metallic thin films.

  6. Optical properties of WO{sub 3} thin films using surface plasmon resonance technique

    Energy Technology Data Exchange (ETDEWEB)

    Paliwal, Ayushi; Sharma, Anjali; Gupta, Vinay, E-mail: drguptavinay@gmail.com, E-mail: vgupta@physics.du.ac.in [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Tomar, Monika [Department of Physics, Miranda House, University of Delhi, Delhi 110007 (India)

    2014-01-28

    Indigenously assembled surface plasmon resonance (SPR) technique has been exploited to study the thickness dependent dielectric properties of WO{sub 3} thin films. WO{sub 3} thin films (80 nm to 200 nm) have been deposited onto gold (Au) coated glass prism by sputtering technique. The structural, optical properties and surface morphology of the deposited WO{sub 3} thin films were studied using X-ray diffraction, UV-visible spectrophotometer, Raman spectroscopy, and Scanning electron microscopy (SEM). XRD analysis shows that all the deposited WO{sub 3} thin films are exhibiting preferred (020) orientation and Raman data indicates that the films possess single phase monoclinic structure. SEM images reveal the variation in grain size with increase in thickness. The SPR reflectance curves of the WO{sub 3}/Au/prism structure were utilized to estimate the dielectric properties of WO{sub 3} thin films at optical frequency (λ = 633 nm). As the thickness of WO{sub 3} thin film increases from 80 nm to 200 nm, the dielectric constant is seen to be decreasing from 5.76 to 3.42, while the dielectric loss reduces from 0.098 to 0.01. The estimated value of refractive index of WO{sub 3} film is in agreement to that obtained from UV-visible spectroscopy studies. The strong dispersion in refractive index is observed with wavelength of incident laser light.

  7. Preparation and Characterization of Sb2Te3 Thin Films by Coevaporation

    Directory of Open Access Journals (Sweden)

    Bin Lv

    2010-01-01

    Full Text Available Deposition of Sb2Te3 thin films on soda-lime glass substrates by coevaporation of Sb and Te is described in this paper. Sb2Te3 thin films were characterized by x-ray diffraction (XRD, x-ray fluorescence (XRF, atomic force microscopy (AFM, x-ray photoelectron spectroscopy (XPS, electrical conductivity measurements, and Hall measurements. The abnormal electrical transport behavior occurred from in situ electrical conductivity measurements. The results indicate that as-grown Sb2Te3 thin films are amorphous and undergo an amorphous-crystalline transition after annealing, and the posttreatment can effectively promote the formation of Sb-Te bond and prevent oxidation of thin film surface.

  8. Solid thin film materials for use in thin film charge-coupled devices

    International Nuclear Information System (INIS)

    Lynch, S.J.

    1983-01-01

    Solid thin films deposited by vacuum deposition were evaluated to ascertain their effectiveness for use in the manufacturing of charge-coupled devices (CCDs). Optical and electrical characteristics of tellurium and Bi 2 Te 3 solid thin films were obtained in order to design and to simulate successfully the operation of thin film (TF) CCDs. In this article some of the material differences between single-crystal material and the island-structured thin film used in TFCCDs are discussed. The electrical parameters were obtained and tabulated, e.g. the mobility, conductivity, dielectric constants, permittivity, lifetime of holes and electrons in the thin films and drift diffusion constants. The optical parameters were also measured and analyzed. After the design was complete, experimental TFCCDs were manufactured and were successfully operated utilizing the aforementioned solid thin films. (Auth.)

  9. Protection of MoO3 high work function by organic thin film

    International Nuclear Information System (INIS)

    Wang, Chenggong; Irfan, Irfan; Gao, Yongli

    2014-01-01

    The effects of air exposure are investigated for molybdenum trioxide (MoO 3 ) covered with organic thin films using ultraviolet photoemission spectroscopy. It is found that the severe drop of the work function of MoO 3 by air exposure is substantially reduced by the organic thin films. Both CuPc and C 60 are used for the investigations. The results indicate that the MoO 3 surface can be passivated by approximately two monolayers of organic thin films against exposure to air

  10. Optical properties of titanium trisulphide (TiS3) thin films

    International Nuclear Information System (INIS)

    Ferrer, I.J.; Ares, J.R.; Clamagirand, J.M.; Barawi, M.; Sánchez, C.

    2013-01-01

    Titanium trisulphide thin films have been grown on quartz substrates by sulphuration of electron-beam evaporated Ti layers (d ∼ 300 nm) in a vacuum sealed ampoule in the presence of sulphur powder at 550 °C for different periods of time (1 to 20 h). Thin films were characterized by X-ray diffraction, energy dispersive analyses of X-ray and scanning electron microscopy. Results demonstrate that films are composed by monoclinic titanium trisulphide. Films show n-type conductivity with a relatively high resistivity (ρ ∼ 4 ± 2 Ω·cm) and high values of the Seebeck coefficient (− 600 μV/K) at room temperature. Values of the optical absorption coefficient about α ∼ 10 5 cm −1 , determined from reflectance and transmittance measurements, have been obtained at photon energies hυ > 2 eV. The absorption coefficient dependence on the photon energy in the range of 1.6–3.0 eV hints the existence of a direct transition with an energy gap between 1.35 and 1.50 eV. By comparing these results with those obtained from bulk TiS 3 , a direct transition with lower energy is also found which could have been hidden due to the low value of the absorption coefficient in this energy range. - Highlights: ► Thin films of TiS 3 have been obtained by sulphuration of Ti layers. ► Optical properties of TiS 3 thin films have been determined. ► Optical energy gap of TiS 3 has been obtained. ► Optical properties of bulk TiS 3 have been measured and compared with those of films

  11. Structural phototransformation of WO{sub 3} thin films detected by photoacoustic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, Argelia Perez, E-mail: ekargy@hotmail.com [Universidad Nacional Autonoma de Mexico, Laboratorio de Fotofisica y Peliculas Delgadas-CCADET, Ciudad Universitaria, Coyoacan, A.P. 70-186, C.P. 04510, Mexico, D.F. (Mexico); Montes de Oca, C. Oliva; Castaneda-Guzman, R.; Garcia, A. Esparza [Universidad Nacional Autonoma de Mexico, Laboratorio de Fotofisica y Peliculas Delgadas-CCADET, Ciudad Universitaria, Coyoacan, A.P. 70-186, C.P. 04510, Mexico, D.F. (Mexico)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The phototransformation of WO{sub 3} thin films were studied by photoacoustic technique. Black-Right-Pointing-Pointer The phase transition in WO{sub 3} thin films was induced by laser irradiation fluence. Black-Right-Pointing-Pointer The onset and end of the phototransformation in the thin films was identified. Black-Right-Pointing-Pointer The ablation threshold for each sample was identified. - Abstract: The photoacoustic technique (PA) was used to detect the phase transformation from amorphous to crystalline state of tungsten oxide (WO{sub 3}) thin films induced by UV pulsed laser radiation at low energy (<1.5 mJ). The evolution of photoacoustic signal was studied by a correlation analysis, comparing successive signals at fluences ranging from 0 to 20 mJ/cm{sup 2}. In this interval, it was possible to observe structural changes and the ablation threshold in films due to incident laser fluence effect. Thin films of WO{sub 3} were deposited by DC reactive magnetron sputtering over glass substrates at different deposition times. The results obtained by correlation analysis were compared with Raman spectroscopy data.

  12. Preparation and characterization of nanocrystalline porous TiO2/WO3 composite thin films

    International Nuclear Information System (INIS)

    Hsu, C.-S.; Lin, C.-K.; Chan, C.-C.; Chang, C.-C.; Tsay, C.-Y.

    2006-01-01

    TiO 2 materials possessing not only photocatalytic but also electrochromic properties have attracted many research and development interests. Though WO 3 exhibits excellent electrochromic properties, the much higher cost and water-sensitivity of WO 3 as compared with the TiO 2 may restrict the practical application of WO 3 materials. In the present study, the feasibility of preparing nanocrystalline porous TiO 2 /WO 3 composite thin films was investigated. Precursors of sols TiO 2 and/or WO 3 and polystyrene microspheres were used to prepare nanocrystalline pure TiO 2 , WO 3 , and composite TiO 2 /WO 3 thin films by spin coating. The spin-coated thin films were amorphous and, after heat treating at a temperature of 500 o C, nanocrystalline TiO 2 , TiO 2 /WO 3 , and WO 3 thin films with or without pores were prepared successfully. The heat-treated thin films were colorless and coloration-bleaching phenomena can be observed during cyclic voltammetry tests. The heat-treated thin films exhibited good reversible electrochromic behavior while the porous TiO 2 /WO 3 composite film exhibited improved electrochromic properties

  13. Metal-insulator transition induced in CaVO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Gu Man [Department of Physics, University of Virginia, 382 McCormick Rd., Charlottesville, Virginia 22904 (United States); Laverock, Jude; Chen, Bo; Smith, Kevin E. [Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215 (United States); Wolf, Stuart A. [Department of Physics, University of Virginia, 382 McCormick Rd., Charlottesville, Virginia 22904 (United States); Department of Materials Science and Engineering, University of Virginia, 395 McCormick Rd., Charlottesville, Virginia 22904 (United States); Lu Jiwei [Department of Materials Science and Engineering, University of Virginia, 395 McCormick Rd., Charlottesville, Virginia 22904 (United States)

    2013-04-07

    Stoichiometric CaVO{sub 3} (CVO) thin films of various thicknesses were grown on single crystal SrTiO{sub 3} (STO) (001) substrates using a pulsed electron-beam deposition technique. The CVO films were capped with a 2.5 nm STO layer. We observed a temperature driven metal-insulator transition (MIT) in CVO films with thicknesses below 4 nm that was not observed in either thick CVO films or STO films. The emergence of this MIT can be attributed to the reduction in effective bandwidth due to a crossover from a three-dimensional metal to a two-dimensional insulator. The insulating phase was only induced with a drive current below 0.1 {mu}A. X-ray absorption measurements indicated different electronic structures for thick and very thin films of CVO. Compared with the thick film ({approx}60 nm), thin films of CVO (2-4 nm) were more two-dimensional with the V charge state closer to V{sup 4+}.

  14. SILAR deposited Bi2S3 thin film towards electrochemical supercapacitor

    Science.gov (United States)

    Raut, Shrikant S.; Dhobale, Jyotsna A.; Sankapal, Babasaheb R.

    2017-03-01

    Bi2S3 thin film electrode has been synthesized by simple and low cost successive ionic layer adsorption and reaction (SILAR) method on stainless steel (SS) substrate at room temperature. The formation of interconnected nanoparticles with nanoporous surface morphology has been achieved and which is favourable to the supercapacitor applications. Electrochemical supercapacitive performance of Bi2S3 thin film electrode has been performed through cyclic voltammetry, charge-discharge and stability studies in aqueous Na2SO4 electrolyte. The Bi2S3 thin film electrode exhibits the specific capacitance of 289 Fg-1 at 5 mVs-1 scan rate in 1 M Na2SO4 electrolyte.

  15. Study of Sb2S3 thin films deposited by SILAR method

    Science.gov (United States)

    Deshpande, M. P.; Chauhan, Krishna; Patel, Kiran N.; Rajput, Piyush; Bhoi, Hiteshkumar R.; Chaki, S. H.

    2018-05-01

    In the present work, we deposited Sb2S3 thin films on glass slide by successive ionic layer adsorption and reaction (SILAR) technique with different time cycles. From EDAX, we could observe that the films were non-stoichiometric and contained few elements from glass slide. X-ray diffraction has shown that these films are orthorhombic in structure from where we have calculated the lattice parameter and crystallize size. SEM images shows that SILAR synthesized Sb2S3 thin films are homogenous and well distributed indicating the formation of uniform thin films at lower concentration. The room temperature Raman spectra of Sb2S3 thin films showed sharp peaks at 250 cm‑1 and 300 cm‑1 for all cases. Room temperature photoluminescence emission spectrum shows broad bands over 430–480 nm range with strong blue emission peak centered at same wavelength of 460 nm (2.70 eV) for all cases.

  16. Improved photoelectrochemical performance of BiVO4/MoO3 heterostructure thin films

    Science.gov (United States)

    Kodan, Nisha; Mehta, B. R.

    2018-05-01

    Bismuth vanadate (BiVO4) and Molybdenum trioxide (MoO3) thin films have been prepared by RF sputtering technique. BiVO4 thin films were deposited on indium doped tin oxide (In: SnO2; ITO) substrates at room temperature and 80W applied rf power. The prepared BiVO4 thin films were further annealed at 450°C for 2 hours in air to obtain crystalline monoclinic phase and successively coated with MoO3 thin films deposited at 150W rf power and 400°C for 30 minutes. The effect of coupling BiVO4 and MoO3 on the structural, optical and photoelectrochemical (PEC) properties have been studied. Optical studies reveal that coupling of BiVO4 and MoO3 results in improvement of optical absorption in visible region of solar spectrum. PEC study shows approximate 3-fold and 38-fold increment in photocurrent values of BiVO4/MoO3 (0.38 mA/cm2) heterostructure thin film as compared to MoO3 (0.15 mA/cm2) and BiVO4 (10 µA/cm2) thin films at applied bias of 1 V vs Ag/AgCl in 0.5 M Na2SO4 (pH=7) electrolyte.

  17. Characterization of MAPLE deposited WO3 thin films for electrochromic applications

    Science.gov (United States)

    Boyadjiev, S. I.; Stefan, N.; Szilágyi, I. M.; Mihailescu, N.; Visan, A.; Mihailescu, I. N.; Stan, G. E.; Besleaga, C.; Iliev, M. T.; Gesheva, K. A.

    2017-01-01

    Tungsten trioxide (WO3) is a widely studied material for electrochromic applications. The structure, morphology and optical properties of WO3 thin films, grown by matrix assisted pulsed laser evaporation (MAPLE) from monoclinic WO3 nano-sized particles, were investigated for their possible application as electrochromic layers. A KrF* excimer (λ=248 nm, ζFWHM=25 ns) laser source was used in all experiments. The MAPLE deposited WO3 thin films were studied by atomic force microscopy (AFM), grazing incidence X-ray diffraction (GIXRD) and Fourier transform infrared spectroscopy (FTIR). Cyclic voltammetry measurements were also performed, and the coloring and bleaching were observed. The morpho-structural investigations disclosed the synthesis of single-phase monoclinic WO3 films consisting of crystalline nano-grains embedded in an amorphous matrix. All thin films showed good electrochromic properties, thus validating application of the MAPLE deposition technique for the further development of electrochromic devices.

  18. Characterization of MAPLE deposited WO3 thin films for electrochromic applications

    International Nuclear Information System (INIS)

    Boyadjiev, S I; Iliev, M T; Stefan, N; Mihailescu, N; Visan, A; Mihailescu, I N; Szilágyi, I M; Stan, G E; Besleaga, C; Gesheva, K A

    2017-01-01

    Tungsten trioxide (WO 3 ) is a widely studied material for electrochromic applications. The structure, morphology and optical properties of WO 3 thin films, grown by matrix assisted pulsed laser evaporation (MAPLE) from monoclinic WO 3 nano-sized particles, were investigated for their possible application as electrochromic layers. A KrF* excimer (λ=248 nm, ζ FWHM =25 ns) laser source was used in all experiments. The MAPLE deposited WO 3 thin films were studied by atomic force microscopy (AFM), grazing incidence X-ray diffraction (GIXRD) and Fourier transform infrared spectroscopy (FTIR). Cyclic voltammetry measurements were also performed, and the coloring and bleaching were observed. The morpho-structural investigations disclosed the synthesis of single-phase monoclinic WO 3 films consisting of crystalline nano-grains embedded in an amorphous matrix. All thin films showed good electrochromic properties, thus validating application of the MAPLE deposition technique for the further development of electrochromic devices. (paper)

  19. Controlled Confinement of Half-metallic 2D Electron Gas in BaTiO3/Ba2FeReO6/BaTiO3 Heterostructures: A First-principles Study

    Science.gov (United States)

    Saha-Dasgupta, Tanusri; Baidya, Santu; Waghmare, Umesh; Paramekanti, Arun

    Using density functional theory calculations, we establish that the half-metallicity of bulk Ba2FeReO6 survives down i to 1 nm thickness in BaTiO3/Ba2FeReO6/BaTiO3 heterostructures grown along the (001) and (111) directions. The confinement of the two-dimensional (2D) electron gas in this quantum well structure arises from the suppressed hybridization between Re/Fe d states and unoccupied Ti d states, and it is further strengthened by polar fields for the (111) direction. This mechanism, distinct from the polar catastrophe, leads to an order of magnitude stronger confinement of the 2D electron gas than that at the LaAlO3/SrTiO3 interface. We further show low-energy bands of (111) heterostructure display nontrivial topological character. Our work opens up the possibility of realizing ultra-thin spintronic devices. Journal Ref: Phys. Rev. B 92, 161106(R) (2015) S.B. and T.S.D thank Department of Science and Technology, India for the support through Thematic Unit of Excellence. AP was supported by NSERC (Canada).

  20. Optical constants of CH3NH3PbBr3 perovskite thin films measured by spectroscopic ellipsometry

    KAUST Repository

    Alias, Mohd Sharizal; Dursun, Ibrahim; Saidaminov, Makhsud I.; Diallo, Elhadj Marwane; Mishra, Pawan; Ng, Tien Khee; Bakr, Osman; Ooi, Boon S.

    2016-01-01

    function) of CH3NH3PbBr3 perovskite thin films using spectroscopic ellipsometry. Due to the existence of voids, the refractive index of the thin films is around 8% less than the single crystals counterpart. The energy bandgap is around 2.309 eV as obtained

  1. Optical properties of the c-axis oriented LiNbO{sub 3} thin film

    Energy Technology Data Exchange (ETDEWEB)

    Shandilya, Swati; Sharma, Anjali [Department of Physics and Astrophysics, University of Delhi, Delhi-110007 (India); Tomar, Monika [Miranda House, University of Delhi, Delhi 110007 (India); Gupta, Vinay, E-mail: drguptavinay@gmail.com [Department of Physics and Astrophysics, University of Delhi, Delhi-110007 (India)

    2012-01-01

    C-axis oriented Lithium Niobate (LiNbO{sub 3}) thin films have been deposited onto epitaxially matched (001) sapphire substrate using pulsed laser deposition technique. Structural and optical properties of the thin films have been studied using the X-ray diffraction (XRD) and UV-Visible spectroscopy respectively. Raman spectroscopy has been used to study the optical phonon modes and defects in the c-axis oriented LiNbO{sub 3} thin films. XRD analysis indicates the presence of stress in the as-grown LiNbO{sub 3} thin films and is attributed to the small lattice mismatch between LiNbO{sub 3} and sapphire. Refractive index (n = 2.13 at 640 nm) of the (006) LiNbO{sub 3} thin films was found to be slightly lower from the corresponding bulk value (n = 2.28). Various factors responsible for the deviation in the refractive index of (006) LiNbO{sub 3} thin films from the corresponding bulk value are discussed and the deviation is mainly attributed to the lattice contraction due to the presence of stress in deposited film.

  2. Effect of lithium doping in BaTiO3 ceramics for vibration sensor application

    Science.gov (United States)

    Praveen, E.; Murugan, S.; Jayakumar, K.

    2018-04-01

    Phase pure undoped and Lithium doped BaTiO3 particles have been synthesized by high temperature solid-state reaction method. Substitution of Lithium at the Ba2+ site in BaTiO3 lattice has been investigated. The structural, vibrational, electrical and mechanical characterization have been carried out. The poled samples were used as a sensing element for the detection of mechanical oscillations and the presence of 80 Hz pulse in the output spectrum manifest the response of the sensor element to the applied mechanical stress. In comparison with pure BaTiO3 the sensitivity of Li doped BaTiO3 is 14 times greater than the pure BaTiO3. This confirms that Li doped BaTiO3 could be an efficient candidate for the functionalization of vibration sensors in space application.

  3. Improvement of β-phase crystal formation in a BaTiO3-modified PVDF membrane

    Science.gov (United States)

    Lin, SHEN; Lei, GONG; Shuhua, CHEN; Shiping, ZHAN; Cheng, ZHANG; Tao, SHAO

    2018-04-01

    In this paper, low temperature plasma is used to modify the surface of barium titanate (BaTiO3) nanoparticles in order to enhance the interfacial compatibility between ferroelectric poly(vinylidene fluoride) (PVDF) and BaTiO3 nanoparticles. The results demonstrate that oxygenic groups are successfully attached to the BaTiO3 surface, and the quantity of the functional groups increases with the treatment voltage. Furthermore, the effect of modified BaTiO3 nanoparticles on the morphology and crystal structure of the PVDF/BaTiO3 membrane is investigated. The results reveal that the dispersion of BaTiO3 nanoparticles in the PVDF matrix was greatly improved due to the modification of the BaTiO3 nanoparticles by air plasma. It is worth noting that the formation of a β-phase in a PVDF/modified BaTiO3 membrane is observably promoted, which results from the strong interaction between PVDF chains and oxygenic groups fixed on the BaTiO3 surface and the better dispersion of BaTiO3 nanoparticles in the PVDF matrix. Besides, the PVDF/modified BaTiO3 membrane at the treatment voltage of 24 kV exhibits a lower water contact angle (≈68.4°) compared with the unmodified one (≈86.7°). Meanwhile, the dielectric constant of PVDF/BaTiO3 nanocomposites increases with the increase of working voltage.

  4. Chemically deposited Sb{sub 2}S{sub 3} thin films for optical recording

    Energy Technology Data Exchange (ETDEWEB)

    Shaji, S; Arato, A; Castillo, G Alan; Palma, M I Mendivil; Roy, T K Das; Krishnan, B [Facultad de IngenierIa Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon, C.P- 66450 (Mexico); O' Brien, J J; Liu, J, E-mail: bkrishnan@fime.uanl.m [Center for Nanoscience and Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One Univ. Blvd., St. Louis, MO - 63121 (United States)

    2010-02-24

    Laser induced changes in the properties of Sb{sub 2}S{sub 3} thin films prepared by chemical bath deposition are described in this paper. Sb{sub 2}S{sub 3} thin films of thickness 550 nm were deposited from a solution containing SbCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3} at 27 {sup 0}C for 5 h. These thin films were irradiated by a 532 nm continuous wave laser beam under different conditions at ambient atmosphere. X-ray diffraction analysis showed amorphous to polycrystalline transformation due to laser exposure of these thin films. Morphology and composition of these films were described. Optical properties of these films before and after laser irradiation were analysed. The optical band gap of the material was decreased due to laser induced crystallization. The results obtained confirm that there is further scope for developing this material as an optical recording media.

  5. CuInS2 thin films obtained through the annealing of chemically deposited In2S3-CuS thin films

    International Nuclear Information System (INIS)

    Pena, Y.; Lugo, S.; Calixto-Rodriguez, M.; Vazquez, A.; Gomez, I.; Elizondo, P.

    2011-01-01

    In this work, we report the formation of CuInS 2 thin films on glass substrates by heating chemically deposited multilayers of copper sulfide (CuS) and indium sulfide (In 2 S 3 ) at 300 and 350 deg. C in nitrogen atmosphere at 10 Torr. CIS thin films were prepared by varying the CuS layer thickness in the multilayers with indium sulfide. The XRD analysis showed that the crystallographic structure of the CuInS 2 (JCPDS 27-0159) is present on the deposited films. From the optical analysis it was estimated the band gap value for the CIS film (1.49 eV). The electrical conductivity varies from 3 x 10 -8 to 3 Ω -1 cm -1 depending on the thickness of the CuS film. CIS films showed p-type conductivity.

  6. Structural and optical properties of cobalt doped multiferroics BiFeO3 nanostructure thin films

    Science.gov (United States)

    Prasannakumara, R.; Naik, K. Gopalakrishna

    2018-05-01

    Bismuth ferrite (BiFeO3) and Cobalt doped BiFeO3 (BiFe1-XCoXO3) nanostructure thin films were deposited on glass substrates by the sol-gel spin coating method. The X-ray diffraction patterns (XRD) of the grown BiFeO3 and BiFe1-XCoXO3 nanostructure thin films showed distorted rhombohedral structure. The shifting of peaks to higher angles was observed in cobalt doped BiFeO3. The surface morphology of the BiFeO3 and BiFe1-XCoXO3 nanostructure thin films were studied using FESEM, an increase in grain size was observed as Co concentration increases. The thickness of the nanostructure thin films was examined using FESEM cross-section. The EDX studies confirmed the elemental composition of the grown BiFeO3 and BiFe1-XCoXO3 nanostructure thin films. The optical characterizations of the grown nanostructure thin films were carried out using FTIR, it confirms the existence of Fe-O and Bi-O bands and UV-Visible spectroscopy shows the increase in optical band gap of the BiFeO3 nanostructure thin films with Co doping by ploting Tauc plot.

  7. Optical properties of BaTiO3 nanoparticles and silver nanoprisms in polymer host matrices

    Science.gov (United States)

    Requena, Sebastian

    Nanocomposites are materials comprised of a host matrix, such as glass or polymer, with embedded nanoparticles. Embedding nanoparticles into the host makes it possible to create materials with properties that are distinctly unique from those of their host and nanoparticle constituents. Nanocomposites can have superior mechanical, thermal, and optical properties compared to their host materials. We characterized the photoluminescent properties of BaTiO3 polymer nanocomposites and the effects of chemically modifying the nanoparticles surface on said properties. BaTiO3 nanopowders of average grain sizes 50 nm and 100 nm were functionalized by (3-aminopropyl)triethoxysilane (3APTS) and mixed with poly(methyl methacrylate)/toluene solution. The nanocomposites films morphology and chemical structure were studied via AFM and FTIR. The photoluminescence spectrum of the pure nanoparticles was composed of an emission at ˜3.0 eV and multiple bands centered at ˜2.5 eV. Surface functionalization of the BaTiO3 nanoparticles via 3APTS increased overall luminescence at room temperature while only enhancing the ˜3.0 eV emission at low-temperature. On the other hand, polymer coating of the functionalized nanoparticles significantly enhances ˜3.0 eV emissions while decreasing emissions associated with near-surface lattice distortions at ˜2.5 eV. Chemical modification of the surface with 3APTS and PMMA presents a pathway to tune and control the photoluminescent properties of BTO nanoparticles. We also present optical studies of two different size distributions of silver triangular nanoprisms, one with a dipole resonance at ˜520 nm and the other with a dipole resonance at ˜650 nm, placed in different media. The silver nanoprisms were embedded in a polyvinyl alcohol (PVA) polymer matrix and oriented by stretching the polymer/nanoprism nanocomposite films. We observe significantly increased linear dichroism in the region associated with the plasmonic in-plane dipole mode upon

  8. Improved electrochromical properties of sol-gel WO3 thin films by doping gold nanocrystals

    International Nuclear Information System (INIS)

    Naseri, N.; Azimirad, R.; Akhavan, O.; Moshfegh, A.Z.

    2010-01-01

    In this investigation, the effect of gold nanocrystals on the electrochromical properties of sol-gel Au doped WO 3 thin films has been studied. The Au-WO 3 thin films were dip-coated on both glass and indium tin oxide coated conducting glass substrates with various gold concentrations of 0, 3.2 and 6.4 mol%. Optical properties of the samples were studied by UV-visible spectrophotometry in a range of 300-1100 nm. The optical density spectra of the films showed the formation of gold nanoparticles in the films. The optical bandgap energy of Au-WO 3 films decreased with increasing the Au concentration. Crystalline structure of the doped films was investigated by X-ray diffractometry, which indicated formation of gold nanocrystals in amorphous WO 3 thin films. X-ray photoelectron spectroscopy (XPS) was used to study the surface chemical composition of the samples. XPS analysis indicated the presence of gold in metallic state and the formation of stoichiometric WO 3 . The electrochromic properties of the Au-WO 3 samples were also characterized using lithium-based electrolyte. It was found that doping of Au nanocrystals in WO 3 thin films improved the coloration time of the layer. In addition, it was shown that variation of Au concentration led to color change in the colored state of the Au-WO 3 thin films.

  9. Structural and electrical properties of Barium Titanate (BaTiO3 and Neodymium doped BaTiO3 (Ba0.995Nd0.005TiO3

    Directory of Open Access Journals (Sweden)

    Tuan Sulong Tuan Amirah

    2017-01-01

    Full Text Available Barium titanate (BaTiO3 and Neodymium (Nd doped BaTiO3 with composition Ba0.995Nd0.005TiO3 were prepared using conventional solid state reaction method to study the dielectric properties of materials. Pure phase samples were found at final heating temperature of 1400°C for overnight. X-ray diffraction analysis reveals the changes in the lattice parameter and unit cell volume of the pure perovskite tetragonal structure with space group (P4mm. Electrical analysis is carried out to investigate the dielectric properties, conductivity behaviour and dielectric loss of BaTiO3 and Ba0.995Nd0.005TiO3. Ba0.995Nd0.005TiO3 have a broaden dielectric peaks with high permittivity of 8000 and reasonably low loss tan δ which is about 0.004 (1 kHz.

  10. Resistivity behavior of optimized PbTiO3 thin films prepared by spin coating method

    Science.gov (United States)

    Nurbaya, Z.; Wahid, M. H.; Rozana, M. D.; Alrokayan, S. A. H.; Khan, H. A.; Rusop, M.

    2018-05-01

    Th is study presents the resistivity behavior of PbTiO3 thin films which were prepared towards metal-insulator-metal capacitor device fabrication. The PbTiO3 thin films were prepared through sol-gel spin coating method that involved various deposition parameters that is (1) different molar concentration of PbTiO3 solutions, (2) various additional PbAc-content in PbTiO3 solutions, and (3) various annealing temperature on PbTiO3 thin films. Hence, an electrical measurement of current versus voltage was done to determine the resistivity behavior of PbTiO3 thin films.

  11. Surface polarization, rumpling, and domain ordering of strained ultrathin BaTiO_3(001) films with in-plane and out-of-plane polarization

    International Nuclear Information System (INIS)

    Dionot, Jelle; Mathieu, Claire; Barrett, Nick; Geneste, Gregory

    2014-01-01

    BaTiO_3 ultrathin films (thickness ≅1.6 nm) with in- and out-of-plane polarization are studied by first-principles calculations. Out-of-plane polarization is simulated using the method proposed by Shimada et al. [Phys. Rev. B 81, 144116 (2010)], which consists in building a supercell containing small domains with alternating up and down polarization. This allows one to investigate the properties of defect free BaTiO_3 ultrathin films with polarization perpendicular to the surface, as a function of in-plane lattice constant, i.e., epitaxial strain. The configurations with polarization perpendicular to the surface (c phase) are found stable under compressive strain, while under tensile strain, the polarization tends to lie in-plane (aa phase), along [110]. In the c phase, the most stable domain width is predicted to be 1 to 2 lattice constants, and the magnitude of the surface rumpling varies according to the direction of the polarization (upwards versus downwards), though its sign is unchanged, the oxygen anions pointing in all cases outwards. Finally, all the surfaces studied are found to be insulating. Analysis of the atom-projected electronic density of states gives insight into the surface contributions to the electronic structure. An important reduction of the Kohn-Sham band gap is predicted at TiO_2 terminations in the c phase (≅1 eV with respect to the aa phase). The Madelung potential at the surface plays the dominant role in modifications of the surface electronic structure. (authors)

  12. Room temperature ferromagnetism in undoped and Ni doped In{sub 2}O{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, N. Sai; Kaleemulla, S., E-mail: skaleemulla@gmail.com; Rao, N. Madhusudhana; Krishnamoorthi, C.; Begam, M. Rigana [Thin Films Laboratory, School of Advanced Sciences, VIT University, Vellore – 632014 (India); Amarendra, G. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603102 (India); UGC-DAE-CSR, Kalpakkam Node, Kokilamedu-603104 (India)

    2015-06-24

    Undoped and Ni (5 at.%) doped In{sub 2}O{sub 3} thin films were deposited on glass substrate using electron beam evaporation technique and Ni doped In{sub 2}O{sub 3} thin films were annealed at 450 oC. A systematic study was carried out on the structural, chemical and magnetic properties of the as deposited and annealed thin films. X-ray diffraction analysis revealed that all the films were cubic in structure and exhibied ferromagnetism at room temperature. The undoped In{sub 2}O{sub 3} thin films exhibited a saturation magnetization of 24.01 emu/cm3. Ni doped In{sub 2}O{sub 3} thin films annealed at 450 oC showed a saturation magnetization of 53.81 emu/cm3.

  13. AC plasma induced modifications in Sb{sub 2}S{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Calixto-Rodriguez, M; Martinez, H [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62210, Cuernavaca, Morelos (Mexico); Castillo, F [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, 04510, Mexico D. F. (Mexico); Pena, Y [Universidad Autonoma de Nuevo Leon, Facultad de Ciencias Quimicas, Pedro de Alba s/n, Cd. Universitaria, San Nicolas de los Garza, N.L (Mexico); Sanchez-Juarez, A, E-mail: ciro@nucleares.unam.m [Centro de Investigacion en EnergIa, Universidad Nacional Autonoma de Mexico, Privada Xochicalco s/n Col. Centro, Temixco, Morelos, C.P. 62580 (Mexico)

    2010-01-01

    Sb{sub 2}S{sub 3} thin films, deposited by the chemical bath deposition method, were treated with N{sub 2} plasma at 3.0 Torr during several minutes. The as-prepared Sb{sub 2}S{sub 3} thin films and films treated with N{sub 2} plasma have been characterized using several techniques. X-ray diffraction studies have shown that plasma treatment induced recrystallization on the as-prepared Sb{sub 2}S{sub 3}thin films. The band gap values decreased from 2.37 to 1.82 eV after plasma treatment, and the electrical conductivity increased from 10{sup 9} to 10{sup 7} ({Omega}cm){sup -1} due to the annealing effect.

  14. Thin-Film Transformation of NH4 PbI3 to CH3 NH3 PbI3 Perovskite: A Methylamine-Induced Conversion-Healing Process.

    Science.gov (United States)

    Zong, Yingxia; Zhou, Yuanyuan; Ju, Minggang; Garces, Hector F; Krause, Amanda R; Ji, Fuxiang; Cui, Guanglei; Zeng, Xiao Cheng; Padture, Nitin P; Pang, Shuping

    2016-11-14

    Methylamine-induced thin-film transformation at room-temperature is discovered, where a porous, rough, polycrystalline NH 4 PbI 3 non-perovskite thin film converts stepwise into a dense, ultrasmooth, textured CH 3 NH 3 PbI 3 perovskite thin film. Owing to the beneficial phase/structural development of the thin film, its photovoltaic properties undergo dramatic enhancement during this NH 4 PbI 3 -to-CH 3 NH 3 PbI 3 transformation process. The chemical origins of this transformation are studied at various length scales. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Temperature behaviour of optical parameters in (Ag3AsS3)0.3(As2S3)0.7 thin films

    Science.gov (United States)

    Kutsyk, Mykhailo M.; Ráti, Yosyp Y.; Izai, Vitalii Y.; Makauz, Ivan I.; Studenyak, Ihor P.; Kökényesi, Sandor; Komada, Paweł; Zhailaubayev, Yerkin; Smailov, Nurzhigit

    2015-12-01

    (Ag3AsS3)0.3(As2S3)0.7 thin films were deposited onto a quartz substrate by rapid thermal evaporation. The optical transmission spectra of thin films were measured in the temperature range 77-300 K. It is shown that the absorption edge spectra are described by the Urbach rule. The temperature behaviour of absorption spectra was studied, the temperature dependences of energy position of absorption edge and Urbach energy were investigated. The influence of transition from three-dimensional glass to the two-dimensional thin film as well as influence of Ag3AsS3 introduction into As2S3 on the optical parameters of (Ag3AsS3)0.3(As2S3)0.7 were analysed. The spectral and temperature behaviour or refractive index for (Ag3AsS3)0.3(As2S3)0.7 thin film were studied.

  16. Silver loaded WO3−x/TiO2 composite multifunctional thin films

    International Nuclear Information System (INIS)

    Dunnill, Charles W.; Noimark, Sacha; Parkin, Ivan P.

    2012-01-01

    Multifunctional WO 3−x –TiO 2 composite thin films have been prepared by sol–gel synthesis and shown to be good visible light photocatalysts whilst retaining a desirable underlying blue colouration. The WO 3−x –TiO 2 composite thin films were further enhanced using silver nanoparticles synthesised in-situ on the surface from the photo-degradation of silver nitrate solution. Thin films were characterised using X-ray diffraction, Raman, Scanning electron microscopy and UV–visible spectroscopy and shown to photo degrade stearic acid, using white light λ = 420–800 nm. - Highlights: ► WO 3−X TiO 2 composite thin films were synthesised by sol–gel methods. ► Blue tinted glass is desirable for the value added glass industry. ► Silver nanoparticle island formation enhances the activity of the films. ► Blue tinted “value added” coated glass is now possible.

  17. Magnetic and electronic properties of SrMnO3 thin films

    Science.gov (United States)

    Mandal, Arup Kumar; Panchal, Gyanendra; Choudhary, R. J.; Phase, D. M.

    2018-05-01

    Single phase hexagonal bulk SrMnO3 (SMO) was prepared by solid state route and it was used for depositing thin films by pulsed laser deposition (PLD) technique on single crystalline (100) oriented SrTiO3 (STO) substrate. X-ray diffraction shows that the thin film is deposited in cubic SrMnO3 phase. From X-ray absorption at the Mn L edge we observed the mixed valency of Mn (Mn3+& Mn4+) due to strain induced by the lattice mismatching between SMO and STO. Due to this mixed valency of Mn ion in SMO film, the ferromagnetic nature is observed at lower temperature because of double exchange. After post annealing with very low oxygen partial pressure, magnetic and electronic property of SMO films are effectively modified.

  18. Characterization of Alq3 thin films by a near-field microwave microprobe.

    Science.gov (United States)

    Hovsepyan, Artur; Lee, Huneung; Sargsyan, Tigran; Melikyan, Harutyun; Yoon, Youngwoon; Babajanyan, Arsen; Friedman, Barry; Lee, Kiejin

    2008-09-01

    We observed tris-8-hydroxyquinoline aluminum (Alq3) thin films dependence on substrate heating temperatures by using a near-field microwave microprobe (NFMM) and by optical absorption at wavelengths between 200 and 900 nm. The changes of absorption intensity at different substrate heating temperatures are correlated to the changes in the sheet resistance of Alq3 thin films.

  19. Solution based approaches for the morphology control of BaTiO3 particulates

    Directory of Open Access Journals (Sweden)

    Florentina Maxim

    2010-09-01

    Full Text Available Within the action COST 539 - ELENA our contribution was aimed at studying solution based approaches for the morphology control of BaTiO3 particulates. Initially, our kinetic analysis and systematic structural and morphological studies, demonstrated that during hydrothermal synthesis from layered titanate nanotubes (TiNTS, BaTiO3 forms via two mechanisms depending on the temperature and time. At low temperatures (90°C, “wild” type BaTiO3 dendritic particles with cubic structure were formed through a phase boundary topotactic reaction. At higher temperatures and/or for longer times time, the reaction is controlled by a dissolution precipitation mechanism and “seaweed” type BaTiO3 dendrites are formed. Our results unambiguously elucidated why TiNTs do not routinely act as templates for the formation of 1D BaTiO3.In our subsequent investigations, the effect of additives on the aqueous and hydrothermal synthesis of BaTiO3 was assessed. We reported that although the tested additives influenced the growth of BaTiO3, their behaviour varied; poly(acrylic acid (PAA adsorbed on specific crystallographic faces changing the growth kinetics and inducing the oriented attachment of the particles; poly(vinyl pyrrolidone (PVP, sodium dodecylsulfate (SDS and hydroxypropylmethylcellulose (HPMC act as growth inhibitors rather than crystal habit modifiers; and DFructose appeared to increase the activation energy for nucleation, resulting in small crystals (26 nm. Our work clearly indicates that the synthesis of 1D nanostructures of complex oxides by chemical methods is non trivial.

  20. Improvement of CH3NH3PbI3 thin film using the additive 1,8-diiodooctane for planar heterojunction perovskite cells

    Science.gov (United States)

    Abdulrahman, Solh; Wang, Chunhua; Cao, Chenghao; Zhang, Chujun; Yang, Junliang; Jiang, Li

    2017-10-01

    The thin-film quality is critical for obtaining high-performance perovskite solar cells (PSCs). The additive 1,8-diiodooctane (DIO) was used to control the morphology and structure of CH3NH3PbI3 perovskite thin films, and planar heterojunction (PHJ) PSCs with an architecture of ITO/PEDOT: PSS/CH3NH3PbI3/PCBM/Al was fabricated. It was found that the DIO played an important role on CH3NH3PbI3 thin-film quality and the performance of PHJ-PSCs. With the optimal volume ratio of 2%, the compact and uniform high-quality CH3NH3PbI3 thin films with enhanced crystallinity and less roughness were achieved, resulting in the great improvement of power conversion efficiency (PCE) from about 4.5% to over 9.0%. The research results indicate that the additive DIO is a simple and effective method to produce high-quality perovskite thin film and accordingly develop high-performance PHJ-PSCs.

  1. Estudio del perfil de defectos y de las propiedades eléctricas de BaTiO3 dopado con Nb y La

    Directory of Open Access Journals (Sweden)

    Castro, M. S.

    2002-02-01

    Full Text Available The aim of this work is to study the impact of two different and typical donor –dopants; Nb2O5 and La2O3, on the electrical properties of BaTiO3. Besides, the influence of Nb5+ and La3+ on the charge compensation mechanism was evaluated. On this way, it was determined that, the defect structure is not only affected by the dopant ion but also by its concentration. Amount of dopant also affects the electrical properties of BaTiO3 ceramics. In fact, for low Nb2O5 or La2O3 concentration, electronic compensation prevails, leading to a low – resistive material with an important PTCR effect. By EPR an increases in the oxygen vacancies with a low lanthanum addition was determined. This phenomenon could be associated to the lanthanum acceptor behavior. On the other hand, high dopant concentration leads to a high – resistive material showing GBBL characteristics. In this case, a high content of double – ionized barium vacancies able to trap electrons, and a thin glassy – phase film covering the BaTiO3 grains lead to a high – resistive material. This phenomenon encourages the hypothesis in which barium vacancies act as acceptor centers at the grain boundaries in BaTiO3 ceramics.En este trabajo, se estudia el impacto de la adición de Nb2O5 o La2O3 sobre las propiedades eléctricas de cerámicos basados en BaTiO3. Asimismo, se estudia la influencia de estos dos típicos dopantes en los mecanismos de compensación de cargas. En este sentido, se ha determinado que la estructura de defectos en el BaTiO3 no sólo se encuentra afectada por el tipo de dopante sino tambien por su concentración. En efecto, para bajas concentraciones de Nb2O5 o La2O3, predomina un mecanismo de compensación de cargas por generación de electrones. Sin embargo, los resultados de EPR muestran que la adición de una pequeña cantidad de La2O3 produce un notable incremento en la concentración de vacantes de oxígeno respecto del BaTiO3 sin dopar. Este fenómeno podr

  2. Cu2SixSn1-xS3 Thin Films Prepared by Reactive Magnetron Sputtering For Low-Cost Thin Film Solar Cells

    Science.gov (United States)

    Yan, Chang; Liu, Fang-Yang; Lai, Yan-Qing; Li, Jie; Liu, Ye-Xiang

    2011-10-01

    We report the preparation of Cu2SixSn1-xS3 thin films for thin film solar cell absorbers using the reactive magnetron co-sputtering technique. Energy dispersive spectrometer and x-ray diffraction analyses indicate that Cu2Si1-xSnxS3 thin films can be synthesized successfully by partly substituting Si atoms for Sn atoms in the Cu2SnS3 lattice, leading to a shrinkage of the lattice, and, accordingly, by 2θ shifting to larger values. The blue shift of the Raman peak further confirms the formation of Cu2SixSn1-xS3. Environmental scanning electron microscope analyses reveal a polycrystalline and homogeneous morphology with a grain size of about 200-300 nm. Optical measurements indicate an optical absorption coefficient of higher than 104 cm-1 and an optical bandgap of 1.17±0.01 eV.

  3. Sol-Gel Synthesis and Characterization of Ba1-xGdxTiO3Thin Films on SiO2/Si Substrates Using Spin-Coating Technique

    Directory of Open Access Journals (Sweden)

    Yen Chin TEH

    2017-02-01

    Full Text Available Ba1-xGdxTiO3+δ, at x = 0, 0.05, 0.1, 0.15, 0.2, (BGT thin films have been fabricated on SiO2/Si substrate using Sol-Gel method. The microstructure and surface morphology of the fabricated films have been investigated using X-ray diffraction (XRD and atomic force microscopy (AFM. The XRD results show that the fabricated films are crystalline with perovskite structure. There is a shifting of the preferred peak at 31.5o to a higher angle as the doping ratio increases suggesting a distortion lattice exists in the films, which could be due to the substitution of Gd3+ ions into Ba-site. The decreasing of lattice constants confirms the substitution of Gd3+ in BaTiO3 lattice structure. The microstrain and dislocation density are found to be increased with the increase of Gd3+ doping, which attributed to the reduction of lattice volume that due to the ionic size mismatch effect. The AFM results show decreasing trend in both average grain size and roughness parameters. Therefore, the microstructure and surface morphology of BGT samples is strongly dependent on the Gd3+ doping concentration that mainly due to the difference ionic radius substitution.DOI: http://dx.doi.org/10.5755/j01.ms.23.1.13954

  4. Magnetoelectric coupling effect in transition metal modified polycrystalline BiFeO3 thin films

    International Nuclear Information System (INIS)

    Sreenivas Puli, Venkata; Kumar Pradhan, Dhiren; Gollapudi, Sreenivasulu; Coondoo, Indrani; Panwar, Neeraj; Adireddy, Shiva; Chrisey, Douglas B.; Katiyar, Ram S.

    2014-01-01

    Rare-earth (Sm) and transition metal (Co) modified polycrystalline BiFeO 3 (BFO) thin films have been deposited on Pt/TiO 2 /SiO 2 /Si substrate successfully through pulsed laser deposition (PLD) technique. Piezoelectric, leakage current and temperature dependent dielectric and magnetic behaviour were investigated for the films. Typical “butterfly-shaped” loop were observed in BSFCO films with an effective piezoelectric constant (d 33 ) ∼94 pm/V at 0.6 MV/cm. High dielectric constant ∼900 and low dielectric loss ∼0.25 were observed at room temperature. M–H loops have shown relatively high saturation magnetization ∼35 emu/cm 3 at a maximum field of H ∼20 kOe. Enhanced magnetoelectric coupling response is observed under applied magnetic field. The multiferroic, piezoelectric, leakage current behaviours were explored. Such studies should be helpful in designing multiferroic materials based on BSFCO films. - Highlights: • Transition metal modified polycrystalline BiFeO 3 thin films prepared using PLD. • High ME-coupling response was observed in co-substituted BiFeO 3 thin films. • High magnetization ∼35 emu/cm 3 at a maximum field of H ∼20 kOe. • Low leakage current might be due to co-substitution in BiFeO 3 thin films. • A notable piezoelectric constant d 33 ∼94 pm/V was found in BiFeO 3 thin films

  5. Dielectric properties of DC reactive magnetron sputtered Al2O3 thin films

    International Nuclear Information System (INIS)

    Prasanna, S.; Mohan Rao, G.; Jayakumar, S.; Kannan, M.D.; Ganesan, V.

    2012-01-01

    Alumina (Al 2 O 3 ) thin films were sputter deposited over well-cleaned glass and Si substrates by DC reactive magnetron sputtering under various oxygen gas pressures and sputtering powers. The composition of the films was analyzed by X-ray photoelectron spectroscopy and an optimal O/Al atomic ratio of 1.59 was obtained at a reactive gas pressure of 0.03 Pa and sputtering power of 70 W. X-ray diffraction results revealed that the films were amorphous until 550 °C. The surface morphology of the films was studied using scanning electron microscopy and the as-deposited films were found to be smooth. The topography of the as-deposited and annealed films was analyzed by atomic force microscopy and a progressive increase in the rms roughness of the films from 3.2 nm to 4.53 nm was also observed with increase in the annealing temperature. Al-Al 2 O 3 -Al thin film capacitors were then fabricated on glass substrates to study the effect of temperature and frequency on the dielectric property of the films. Temperature coefficient of capacitance, AC conductivity and activation energy were determined and the results are discussed. - Highlights: ► Al 2 O 3 thin films were deposited by DC reactive magnetron sputtering. ► The films were found to be amorphous up to annealing temperature of 550 C. ► An increase in rms roughness of the films was observed with annealing. ► Al-Al 2 O 3 -Al thin film capacitors were fabricated and dielectric constant was 7.5. ► The activation energy decreased with increase in frequency.

  6. Effect of Annealing Temperature on Flowerlike Cu3BiS3 Thin Films Grown by Chemical Bath Deposition

    Science.gov (United States)

    Deshmukh, S. G.; Patel, S. J.; Patel, K. K.; Panchal, A. K.; Kheraj, Vipul

    2017-10-01

    For widespread application of thin-film photovoltaic solar cells, synthesis of inexpensive absorber material is essential. In this work, deposition of ternary Cu3BiS3 absorber material, which contains abundant and environmentally benign elements, was carried out on glass substrate. Flowerlike Cu3BiS3 thin films with nanoflakes as building block were formed on glass substrate by chemical bath deposition. These films were annealed at 573 K and 673 K in sulfur ambient for structural improvement. Their structure was characterized using Raman spectroscopy, as well as their surface morphological and optical properties. The x-ray diffraction profile of as-deposited Cu3BiS3 thin film revealed amorphous structure, which transformed to orthorhombic phase after annealing. The Raman spectrum exhibited a characteristic peak at 290 cm-1. Scanning electron microscopy of as-deposited Cu3BiS3 film confirmed formation of nanoflowers with diameter of around 1052 nm. Wettability testing of as-deposited Cu3BiS3 thin film demonstrated hydrophobic nature, which became hydrophilic after annealing. The measured ultraviolet-visible (UV-Vis) absorption spectra of the Cu3BiS3 thin films gave an absorption coefficient of 105 cm-1 and direct optical bandgap of about 1.42 eV after annealing treatment. Based on all these results, such Cu3BiS3 material may have potential applications in the photovoltaic field as an absorber layer.

  7. Fe3O4 thin films sputter deposited from iron oxide targets

    International Nuclear Information System (INIS)

    Peng, Yingguo; Park, Chandro; Laughlin, David E.

    2003-01-01

    Fe 3 O 4 thin films have been directly sputter deposited from a target consisting of a mixture of Fe 3 O 4 and Fe 2 O 3 onto Si and glass substrates. The magnetic properties and microstructures of the films have been characterized and correlated. The columnar growth of the Fe 3 O 4 grains was found to be initialized from the substrate surface without any critical thickness. Substrate bias was found to be a very effective means of improving the crystal quality and magnetic properties of the thin films. The crystallographic defects revealed by high resolution transmission electron microscopy seem to be a characteristic of the films prepared by this method

  8. Thickness control in electrophoretic deposition of WO3 nanofiber thin films for solar water splitting

    International Nuclear Information System (INIS)

    Fang, Yuanxing; Lee, Wei Cheat; Canciani, Giacomo E.; Draper, Thomas C.; Al-Bawi, Zainab F.; Bedi, Jasbir S.; Perry, Christopher C.; Chen, Qiao

    2015-01-01

    Graphical abstract: - Highlights: • A novel method combining electrospinning and electrophoretic deposition was established for the creation of nanostructured semiconductor thin films. • The created thin films displayed a high chemical stability with a controllable thickness. • The PEC water splitting performance of the thin films was optimized by fine-tuning the thickness of the films. • A maximum photoconversion efficiency was achieved by 18 μm nanofibrous thin films. - Abstract: Electrophoretic deposition (EPD) of ground electrospun WO 3 nanofibers was applied to create photoanodes with controlled morphology for the application of photoelectrochemical (PEC) water splitting. The correlations between deposition parameters and film thicknesses were investigated with theoretical models to precisely control the morphology of the nanostructured porous thin film. The photoconversion efficiency was further optimized as a function of film thickness. A maximum photoconversion efficiency of 0.924% from electrospun WO 3 nanofibers that EPD deposited on a substrate was achieved at a film thickness of 18 μm.

  9. Orientation control of chemical solution deposited LaNiO3 thin films

    International Nuclear Information System (INIS)

    Ueno, Kengo; Yamaguchi, Toshiaki; Sakamoto, Wataru; Yogo, Toshinobu; Kikuta, Koichi; Hirano, Shin-ichi

    2005-01-01

    High quality LaNiO 3 (LNO) thin films with preferred orientation could be synthesized on Pt/Ti/SiO 2 /Si substrates at 700 deg. C using the chemical solution deposition method. The homogeneous and stable LNO precursor solutions were prepared using lanthanum isopropoxide and nickel (II) acetylacetonate in a mixed solvent of absolute ethanol and 2-methoxyethanol. The oriented LNO thin films exhibit metallic electro-conduction, and their resistivity at room temperature is sufficiently low for making them an alternative electrode material for functional ceramic thin films

  10. Modified chemical synthesis of porous α-Sm{sub 2}S{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kumbhar, V.S.; Jagadale, A.D. [Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur, (M.S.) 416004 (India); Gaikwad, N.S. [Rayat Shikshan Sanstha, Satara, (M.S.) 415 001 (India); Lokhande, C.D., E-mail: l_chandrakant@yahoo.com [Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur, (M.S.) 416004 (India)

    2014-08-15

    Highlights: • A novel chemical route to prepare α-Sm{sub 2}S{sub 3} thin films. • A porous honeycomb like morphology of the α-Sm{sub 2}S{sub 3} thin film. • An application of α-Sm{sub 2}S{sub 3} thin film toward its supercapacitive behaviour. - Abstract: The paper reports synthesis of porous α-Sm{sub 2}S{sub 3} thin films using modified chemical synthesis, also known as successive ionic layer adsorption and reaction (SILAR) method. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), wettability and ultraviolet–visible spectroscopy (UV–vis) techniques are used for the study of structural, elemental, morphological and optical properties of α-Sm{sub 2}S{sub 3} films. An orthorhombic crystal structure of α-Sm{sub 2}S{sub 3} is resulted from XRD study. The SEM and AFM observations showed highly porous α-Sm{sub 2}S{sub 3} film surface. An optical band gap of 2.50 eV is estimated from optical absorption spectrum. The porous α-Sm{sub 2}S{sub 3} thin film tuned for supercapacitive behaviour using cyclic voltammetry and galvanostatic charge discharge showed a specific capacitance and energy density of 294 Fg{sup –1} and 48.9 kW kg{sup –1}, respectively in 1 M LiClO{sub 4}–propylene carbonate electrolyte.

  11. Synthesis and luminescence properties of BaTiO3:RE (RE = Gd , Dy ...

    Indian Academy of Sciences (India)

    thermoluminescence (TL) properties of BaTiO3 samples doped with Gd3+, Dy3+, Tb3+ and Lu3+ were investigated. ... electron microscope using an accelerating voltage of 20 kV. .... doping of 1% mole Gd3+ ion into the BaTiO3 compound.

  12. Oxygen vacancy induced room temperature ferromagnetism in (In1-xNix)2O3 thin films

    Science.gov (United States)

    Chakraborty, Deepannita; Kaleemulla, S.; Kuppan, M.; Rao, N. Madhusudhana; Krishnamoorthi, C.; Omkaram, I.; Reddy, D. Sreekantha; Rao, G. Venugopal

    2018-05-01

    Nickel doped indium oxide thin films (In1-xNix)2O3 at x = 0.00, 0.03, 0.05 and 0.07 were deposited onto glass substrates by electron beam evaporation technique. The deposited thin films were subjected to annealing in air at 250 °C, 350 °C and 450 °C for 2 h using high temperature furnace. A set of films were vacuum annealed at 450 °C to study the role of oxygen on magnetic properties of the (In1-xNix)2O3 thin films. The thin films were subjected to different characterization techniques to study their structural, chemical, surface, optical and magnetic properties. All the synthesized air annealed and vacuum annealed films exhibit body centered cubic structure without any secondary phases. No significant change in the diffraction peak position, either to lower or higher diffraction angles has been observed. The band gap of the films decreased from 3.73 eV to 3.63 eV with increase of annealing temperature from 250 °C to 450 °C, in the presence of air. From a slight decrease in strength of magnetization to a complete disappearance of hysteresis loop has been observed in pure In2O3 thin films with increasing the annealing temperature from 250 °C to 450 °C, in the presence of air. The (In1-xNix)2O3 thin films annealed under vacuum follow a trend of enhancement in the strength of magnetization to increase in temperature from 250 °C to 450 °C. The hysteresis loop does not disappear at 450 °C in (In1-xNix)2O3 thin films, as observed in the case of pure In2O3 thin films.

  13. Conductivity of CH{sub 3}NH{sub 3}PbI{sub 3} thin film perovskite stored in ambient atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Gebremichael, Bizuneh, E-mail: bizunehme@gmail.com [Physics Department, Addis Ababa University, Addis Ababa, P.O. Box 1176 (Ethiopia); Alemu, Getachew [Physics Department, Addis Ababa University, Addis Ababa, P.O. Box 1176 (Ethiopia); Tessema Mola, Genene [School of Chemistry & Physics, University of KwaZulu-Nat al, Pietermaritzburg Campus, Private Bag X01, Scottsville 3209 (South Africa)

    2017-06-01

    Time dependent conductivity loss in CH{sub 3}NH{sub 3}PbI{sub 3} thin film perovskite stored in ambient atmosphere were studied based on electrical and optical measurements. Recent investigations on thin film perovskite solar cell suggest that in the steady state operation of the device, the V{sub oc} is unchanged by continuous illumination of light. Rather the reduction in the power conversion efficiency is caused by significant reduction of the short circuit current (J{sub sc}). In this paper, the effect of light on the optical absorption and electrical conductivity of the CH{sub 3}NH{sub 3}PbI{sub 3} thin film which is deposited on a glass substrate is investigated. The temperature dependent conductivity measurements indicated that the dominant conduction mechanism in the film perovskite is electronic rather than ionic.

  14. Strain-Induced Ferromagnetism in Antiferromagnetic LuMnO3 Thin Films

    Science.gov (United States)

    White, J. S.; Bator, M.; Hu, Y.; Luetkens, H.; Stahn, J.; Capelli, S.; Das, S.; Döbeli, M.; Lippert, Th.; Malik, V. K.; Martynczuk, J.; Wokaun, A.; Kenzelmann, M.; Niedermayer, Ch.; Schneider, C. W.

    2013-07-01

    Single phase and strained LuMnO3 thin films are discovered to display coexisting ferromagnetic and antiferromagnetic orders. A large moment ferromagnetism (≈1μB), which is absent in bulk samples, is shown to display a magnetic moment distribution that is peaked at the highly strained substrate-film interface. We further show that the strain-induced ferromagnetism and the antiferromagnetic order are coupled via an exchange field, therefore demonstrating strained rare-earth manganite thin films as promising candidate systems for new multifunctional devices.

  15. Stress-Induced Cubic-to-Hexagonal Phase Transformation in Perovskite Nanothin Films.

    Science.gov (United States)

    Cao, Shi-Gu; Li, Yunsong; Wu, Hong-Hui; Wang, Jie; Huang, Baoling; Zhang, Tong-Yi

    2017-08-09

    The strong coupling between crystal structure and mechanical deformation can stabilize low-symmetry phases from high-symmetry phases or induce novel phase transformation in oxide thin films. Stress-induced structural phase transformation in oxide thin films has drawn more and more attention due to its significant influence on the functionalities of the materials. Here, we discovered experimentally a novel stress-induced cubic-to-hexagonal phase transformation in the perovskite nanothin films of barium titanate (BaTiO 3 ) with a special thermomechanical treatment (TMT), where BaTiO 3 nanothin films under various stresses are annealed at temperature of 575 °C. Both high-resolution transmission electron microscopy and Raman spectroscopy show a higher density of hexagonal phase in the perovskite thin film under higher tensile stress. Both X-ray photoelectron spectroscopy and electron energy loss spectroscopy does not detect any change in the valence state of Ti atoms, thereby excluding the mechanism of oxygen vacancy induced cubic-to-hexagonal (c-to-h) phase transformation. First-principles calculations show that the c-to-h phase transformation can be completed by lattice shear at elevated temperature, which is consistent with the experimental observation. The applied bending plus the residual tensile stress produces shear stress in the nanothin film. The thermal energy at the elevated temperature assists the shear stress to overcome the energy barriers during the c-to-h phase transformation. The stress-induced phase transformation in perovskite nanothin films with TMT provides materials scientists and engineers a novel approach to tailor nano/microstructures and properties of ferroelectric materials.

  16. First-principles calculations on the four phases of BaTiO3.

    Science.gov (United States)

    Evarestov, Robert A; Bandura, Andrei V

    2012-04-30

    The calculations based on linear combination of atomic orbitals basis functions as implemented in CRYSTAL09 computer code have been performed for cubic, tetragonal, orthorhombic, and rhombohedral modifications of BaTiO(3) crystal. Structural and electronic properties as well as phonon frequencies were obtained using local density approximation, generalized gradient approximation, and hybrid exchange-correlation density functional theory (DFT) functionals for four stable phases of BaTiO(3). A comparison was made between the results of different DFT techniques. It is concluded that the hybrid PBE0 [J. P. Perdew, K. Burke, M. Ernzerhof, J. Chem. Phys. 1996, 105, 9982.] functional is able to predict correctly the structural stability and phonon properties both for cubic and ferroelectric phases of BaTiO(3). The comparative phonon symmetry analysis in BaTiO(3) four phases has been made basing on the site symmetry and irreducible representation indexes for the first time. Copyright © 2012 Wiley Periodicals, Inc.

  17. Orthorhombic strontium titanate in BaTiO sub 3 -SrTiO sub 3 superlattices

    CERN Document Server

    Rios, S; Jiang, A Q; Scott, J F; Lü, H; Chen, Z

    2003-01-01

    It has been suggested by several authors that SrTiO sub 3 layers in SrTiO sub 3 -BaTiO sub 3 superlattices should be tetragonal and ferroelectric at ambient temperatures, like the BaTiO sub 3 layers, rather than cubic, as in bulk SrTiO sub 3 , and that free-energy minimization requires continuity of the polarization direction. A recent ab initio calculation constrained solutions to this structure. Surprisingly, our x-ray study shows that the SrTiO sub 3 layers are orthorhombic with 0.03% in-plane strain, with the BaTiO sub 3 c-axis matching the SrTiO sub 3 a- and b-axis better than the c-axis; strain energy overcomes the cost in electrostatic energy. (letter to the editor)

  18. Effects of applied electric field during postannealing on the tunable properties of (Ba,Sr)TiO3 thin films

    International Nuclear Information System (INIS)

    Xia Yidong; Cheng Jinbo; Pan Bai; Wu Di; Meng Xiangkang; Liu Zhiguo

    2005-01-01

    The impact of postannealing in electric field on the structure, tunability, and dielectric behavior of rf magnetron sputtering derived (Ba,Sr)TiO 3 films has been studied. It has been demonstrated that postannealing in the proper electric field can increase the dielectric constant and the tunability remarkably and destroy the symmetry of capacitance-voltage characteristics of the films. The increased out-of-plane lattice constant and the appearance of the hysteresis loops in the electric-annealed films indicated the formation of small polar regions with tetragonal structure, which are responsible for the increased dielectric constant and tunability. It was proposed that the segregation of Ti 3+ ions caused by electric annealing could induce the formation of BaTiO 3 -like regions, which are ferroelectric at room temperature

  19. Effects of applied electric field during postannealing on the tunable properties of (Ba,Sr)TiO3 thin films

    Science.gov (United States)

    Xia, Yidong; Cheng, Jinbo; Pan, Bai; Wu, Di; Meng, Xiangkang; Liu, Zhiguo

    2005-08-01

    The impact of postannealing in electric field on the structure, tunability, and dielectric behavior of rf magnetron sputtering derived (Ba,Sr)TiO3 films has been studied. It has been demonstrated that postannealing in the proper electric field can increase the dielectric constant and the tunability remarkably and destroy the symmetry of capacitance-voltage characteristics of the films. The increased out-of-plane lattice constant and the appearance of the hysteresis loops in the electric-annealed films indicated the formation of small polar regions with tetragonal structure, which are responsible for the increased dielectric constant and tunability. It was proposed that the segregation of Ti3+ ions caused by electric annealing could induce the formation of BaTiO3-like regions, which are ferroelectric at room temperature.

  20. Multiferroic BiFeO{sub 3} thin films: Structural and magnetic characterization

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Z. [Physics Department, Faculty of Science (Girls Branch), Al-Azhar University, Cairo (Egypt); Atta, A. [National Center for Radiation Research and Technology (NCRRT), Nasr City, Cairo (Egypt); Abbas, Y. [Physics Department, Faculty of Science, Suez Canal University, Ismailia (Egypt); Sedeek, K.; Adam, A.; Abdeltwab, E. [Physics Department, Faculty of Science (Girls Branch), Al-Azhar University, Cairo (Egypt)

    2015-02-27

    BiFeO{sub 3} (BFO) film has been deposited on indium tin oxide (ITO) substrate by a simple sol–gel spin-coating technique. The crystal phase composition, surface morphology, topography and magnetization measurements of the BFO thin film were investigated using grazing incidence X-ray diffraction (GIXRD), scanning electronic microscope (SEM), atomic force microscope and vibrating sample magnetometer, respectively. GIXRD analysis revealed that the film was fully crystallized and no impure phase was observed. Cross-section SEM results indicated that compact and homogeneous BFO thin film was deposited on ITO with a thickness of about 180 nm. Moreover, most of A and E-symmetry normal modes of R3c BFO were assigned by Raman spectroscopy. We report here that the pure phase BFO film shows ferromagnetism at room temperature with remarkably high saturation magnetization of 63 kA m{sup −1}. Our results are discussed mainly in correlation with the condition of processing technique and destruction of the spiral spin cycloid at interface layers and grain boundaries. - Highlights: • Multiferroic BiFeO{sub 3} (BFO) thin film was prepared by sol–gel spin-coating method. • BFO film w asdeposited on indium tin oxide substrate with a thickness of 180 nm. • The film exhibits pure rhombohedral perovskite structure. • High saturation magnetization was recorded for our film at room temperature.

  1. Photoconductivity in BiFeO3 thin films

    Science.gov (United States)

    Basu, S. R.; Martin, L. W.; Chu, Y. H.; Gajek, M.; Ramesh, R.; Rai, R. C.; Xu, X.; Musfeldt, J. L.

    2008-03-01

    The optical properties of epitaxial BiFeO3 thin films have been characterized in the visible range. Variable temperature spectra show an absorption onset near 2.17eV, a direct gap (2.667±0.005eV at 300K), and charge transfer excitations at higher energy. Additionally, we report photoconductivity in BiFeO3 films under illumination from a 100mW /cm2 white light source. A direct correlation is observed between the magnitude of the photoconductivity and postgrowth cooling pressure. Dark conductivities increased by an order of magnitude when comparing films cooled in 760 and 0.1Torr. Large increases in photoconductivity are observed in light.

  2. Superconducting thin films of YBa2Cu3O7-x

    International Nuclear Information System (INIS)

    Hudner, J.

    1993-01-01

    Thin films of the high temperature superconductor YBa 2 Cu 3 O 7-x (YBCO) are of significance in fundamental studies of oxide superconductors and for prospected electronic applications based on superconductors operating at liquid nitrogen temperatures (T= 77 K). Synthesis of YBCO thin films is complex and a large part of this thesis has been devoted to the elaboration of various techniques in forming YBCO thin films. A general observation was that synthesis of YBCO films exhibiting high zero-resistivity temperatures temperatures (T c ) ≥ 88 K and elevated critical current densities (J c ) ≥ 10 6 A/cm 2 at 77 K was possible under widely different conditions of film growth. For the BaF 2 -based method, various substrate materials were investigated. Among perovskite related substrates with low losses in the high frequency regime, LaA10 3 was found to yield YBCO films exhibiting the highest quality electrical properties. A study of YBCO film interaction with sapphire substrates was performed. It was suggested that the YBCO film on sapphire consists of weakly coupled superconducting grains. Compositional effects of Y, BA and Cu for MOCVD-YBCO films were examined with respect to morphology, structure, resistivity, as susceptibility and J c (T). High T c :s and J c :s were observed for an anomalous large compositional range of Cu in off-compositional YBCO films. This was shown to be related to the formation of Cu-rich precipitates embedded within a c-Axis oriented stoichiometric YBCO film matrix. Thermal critical current behavior at zero field in thin films of YBCO fabricated by various methods has been studied by three techniques: transport measurements on patterned microbridges, dc magnetization hysteresis loops using the Bean model and non-linear ac susceptibility analysis. Absolute critical current values obtained form the two former techniques when measured on the same YBCO film were observed to differ about a factor of two. The feasibility of non-linear ac

  3. Photoluminescence in Spray Pyrolysis Deposited β-In2S3 Thin Films

    Science.gov (United States)

    Jayakrishnan, R.

    2018-04-01

    Spray pyrolysis deposited In2S3 thin films exhibit two prominent photoluminescent emissions. One of the emissions is green in color and centered at around ˜ 540 nm and the other is centered at around ˜ 690 nm and is red in color. The intensity of the green emission decreases when the films are subjected to annealing in air or vacuum. The intensity of red emission increases when films are air annealed and decreases when vacuum annealed. Vacuum annealing leads to an increase in work function whereas air annealing leads to a decrease in work function for this thin film system relative to the as deposited films indicating changes in space charge regions. Surface photovoltage analysis using a Kelvin probe leads to the conclusion that inversion of band bending occurs as a result of annealing. Correlating surface contact potential measurements using a Kelvin probe, x-ray photoelectron spectroscopy and photoluminescence, we conclude that the surface passivation plays a critical role in controlling the photoluminescence from the spray pyrolysis deposited for In2S3 thin films.

  4. Synthesis and characterization of MoO3–WO3 composite thin films ...

    Indian Academy of Sciences (India)

    Abstract. In order to achieve high colouration efficiency, MoO3–WO3 composite thin films have been successfully deposited on sodium silicate glass and silicon wafer (111) at 30 ◦C by a very simple novel wet process known as liquid phase deposition. The deposited films were annealed at different temperatures and ...

  5. Chemical solution deposition of CaCu3Ti4O12 thin film

    Indian Academy of Sciences (India)

    Administrator

    CaCu3Ti4O12; thin film; chemical solution deposition; dielectric properties. 1. Introduction. The CaCu3Ti4O12. (CCTO) compound has recently attracted considerable ... and Kelvin probe force microscopy (Chung et al 2004). Intrinsic .... SEM images of CCTO thin films as a function of sintering temperature. silicon based ...

  6. Magnetoelectric effect in Cr2O3 thin films

    Science.gov (United States)

    He, Xi; Wang, Yi; Sahoo, Sarbeswar; Binek, Christian

    2008-03-01

    Magnetoelectric materials experienced a recent revival as promising components of novel spintronic devices [1, 2, 3]. Since the magnetoelectric (ME) effect is relativistically small in traditional antiferromagnetic compounds like Cr2O3 (max. αzz 4ps/m ) and also cross- coupling between ferroic order parameters is typically small in the modern multiferroics, it is a challenge to electrically induce sufficient magnetization required for the envisioned device applications. A straightforward approach is to increase the electric field at constant voltage by reducing the thickness of the ME material to thin films of a few nm. Since magnetism is known to be affected by geometrical confinement thickness dependence of the ME effect in thin film Cr2O3 is expected. We grow (111) textured Cr2O3 films with various thicknesses below 500 nm and study the ME effect for various ME annealing conditions as a function of temperature with the help of Kerr-magnetometry. [1] P. Borisov et al. Phys. Rev. Lett. 94, 117203 (2005). [2] Ch. Binek, B.Doudin, J. Phys. Condens. Matter 17, L39 (2005). [3] R. Ramesh and Nicola A. Spaldin 2007 Nature Materials 6 21.

  7. Silver loaded WO{sub 3-x}/TiO{sub 2} composite multifunctional thin films

    Energy Technology Data Exchange (ETDEWEB)

    Dunnill, Charles W.; Noimark, Sacha; Parkin, Ivan P., E-mail: I.P.Parkin@ucl.ac.uk

    2012-06-30

    Multifunctional WO{sub 3-x}-TiO{sub 2} composite thin films have been prepared by sol-gel synthesis and shown to be good visible light photocatalysts whilst retaining a desirable underlying blue colouration. The WO{sub 3-x}-TiO{sub 2} composite thin films were further enhanced using silver nanoparticles synthesised in-situ on the surface from the photo-degradation of silver nitrate solution. Thin films were characterised using X-ray diffraction, Raman, Scanning electron microscopy and UV-visible spectroscopy and shown to photo degrade stearic acid, using white light {lambda} = 420-800 nm. - Highlights: Black-Right-Pointing-Pointer WO{sub 3-X} TiO{sub 2} composite thin films were synthesised by sol-gel methods. Black-Right-Pointing-Pointer Blue tinted glass is desirable for the value added glass industry. Black-Right-Pointing-Pointer Silver nanoparticle island formation enhances the activity of the films. Black-Right-Pointing-Pointer Blue tinted 'value added' coated glass is now possible.

  8. Growth and structure of thermally evaporated Bi{sub 2}Te{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Rogacheva, E.I., E-mail: rogacheva@kpi.kharkov.ua [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze St., Kharkov 61002 (Ukraine); Budnik, A.V. [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze St., Kharkov 61002 (Ukraine); Dobrotvorskaya, M.V.; Fedorov, A.G.; Krivonogov, S.I.; Mateychenko, P.V. [Institute for Single Crystals of NAS of Ukraine, 60 Lenin Prospect, Kharkov 61001 (Ukraine); Nashchekina, O.N.; Sipatov, A.Yu. [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze St., Kharkov 61002 (Ukraine)

    2016-08-01

    The growth mechanism, microstructure, and crystal structure of the polycrystalline n-Bi{sub 2}Te{sub 3} thin films with thicknesses d = 15–350 nm, prepared by thermal evaporation in vacuum onto glass substrates, were studied. Bismuth telluride with Te excess was used as the initial material for the thin film preparation. The thin film characterization was performed using X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, scan electron microscopy, and electron force microscopy. It was established that the chemical composition of the prepared films corresponded rather well to the starting material composition and the films did not contain any phases apart from Bi{sub 2}Te{sub 3}. It was shown that the grain size and the film roughness increased with increasing film thickness. The preferential growth direction changed from [00l] to [015] under increasing d. The X-ray photoelectron spectroscopy studies showed that the thickness of the oxidized surface layer did not exceed 1.5–2.0 nm and practically did not change in the process of aging at room temperature, which is in agreement with the results reported earlier for single crystals. The obtained data show that using simple and inexpensive method of thermal evaporation in vacuum and appropriate technological parameters, one can grow n-Bi{sub 2}Te{sub 3} thin films of a sufficiently high quality. - Highlights: • The polycrystalline n-Bi{sub 2}Te{sub 3} thin films were grown thermal evaporation onto glass. • The growth mechanism and film structure were studied by different structure methods. • The grain size and film roughness increased with increasing film thickness. • The growth direction changes from [00l] to [015] under film thickness increasing. • The oxidized layer thickness (1–2 nm) did not change under aging at room temperature.

  9. Electrochromism and photocatalysis in dendrite structured Ti:WO3 thin films grown by sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Karuppasamy, A., E-mail: karuppasamy@psnacet.edu.in

    2015-12-30

    Graphical abstract: - Highlights: • Dendrite structured Ti doped WO{sub 3} (WTO) thin films are grown by co-sputtering. • Sputtering condition influences structure and surface morphology of WTO films. • Titanium doping and annealing lead to dendritic surface structures in WTO films. • Structural, optical, electrochromic and photocatalytic properties of WTO films. • Enhanced electrochromism and photocatalysis in dendrite structured WTO thin films. - Abstract: Titanium doped tungsten oxide (Ti:WO{sub 3}) thin films with dendrite surface structures were grown by co-sputtering titanium and tungsten in Ar + O{sub 2} atmosphere. Ti:WO{sub 3} thin films were deposited at oxygen flow rates corresponding to pressures in the range 1.0 × 10{sup −3}–5.0 × 10{sup −3} mbar. Argon flow rate and sputtering power densities for titanium (2 W/cm{sup 2}) and tungsten (3 W/cm{sup 2}) were kept constant. Ti:WO{sub 3} films deposited at an oxygen pressure of 5 × 10{sup −3} mbar are found to be better electrochromic and photocatalytic. They have high optical modulation (80% at λ = 550 nm), coloration efficiency (60 cm{sup 2}/C at λ = 550 nm), electron/ion storage and removal capacity (Qc: −22.01 mC/cm{sup 2}, Qa: 17.72 mC/cm{sup 2}), reversibility (80%) and methylene blue decomposition rate (−1.38 μmol/l d). The combined effects of titanium doping, dendrite surface structures and porosity leads to significant enhancement in the electrochromic and photocatalytic properties of Ti:WO{sub 3} films.

  10. Electrochromism and photocatalysis in dendrite structured Ti:WO3 thin films grown by sputtering

    International Nuclear Information System (INIS)

    Karuppasamy, A.

    2015-01-01

    Graphical abstract: - Highlights: • Dendrite structured Ti doped WO 3 (WTO) thin films are grown by co-sputtering. • Sputtering condition influences structure and surface morphology of WTO films. • Titanium doping and annealing lead to dendritic surface structures in WTO films. • Structural, optical, electrochromic and photocatalytic properties of WTO films. • Enhanced electrochromism and photocatalysis in dendrite structured WTO thin films. - Abstract: Titanium doped tungsten oxide (Ti:WO 3 ) thin films with dendrite surface structures were grown by co-sputtering titanium and tungsten in Ar + O 2 atmosphere. Ti:WO 3 thin films were deposited at oxygen flow rates corresponding to pressures in the range 1.0 × 10 −3 –5.0 × 10 −3 mbar. Argon flow rate and sputtering power densities for titanium (2 W/cm 2 ) and tungsten (3 W/cm 2 ) were kept constant. Ti:WO 3 films deposited at an oxygen pressure of 5 × 10 −3 mbar are found to be better electrochromic and photocatalytic. They have high optical modulation (80% at λ = 550 nm), coloration efficiency (60 cm 2 /C at λ = 550 nm), electron/ion storage and removal capacity (Qc: −22.01 mC/cm 2 , Qa: 17.72 mC/cm 2 ), reversibility (80%) and methylene blue decomposition rate (−1.38 μmol/l d). The combined effects of titanium doping, dendrite surface structures and porosity leads to significant enhancement in the electrochromic and photocatalytic properties of Ti:WO 3 films.

  11. Mechanism of Crystallization and Implications for Charge Transport in Poly(3-ethylhexylthiophene) Thin Films

    KAUST Repository

    Duong, Duc T.

    2014-04-09

    In this work, crystallization kinetics and aggregate growth of poly(3-ethylhexylthiophene) (P3EHT) thin films are studied as a function of film thickness. X-ray diffraction and optical absorption show that individual aggregates and crystallites grow anisotropically and mostly along only two packing directions: the alkyl stacking and the polymer chain backbone direction. Further, it is also determined that crystallization kinetics is limited by the reorganization of polymer chains and depends strongly on the film thickness and average molecular weight. Time-dependent, field-effect hole mobilities in thin films reveal a percolation threshold for both low and high molecular weight P3EHT. Structural analysis reveals that charge percolation requires bridged aggregates separated by a distance of ≈2-3 nm, which is on the order of the polymer persistence length. These results thus highlight the importance of tie molecules and inter-aggregate distance in supporting charge percolation in semiconducting polymer thin films. The study as a whole also demonstrates that P3EHT is an ideal model system for polythiophenes and should prove to be useful for future investigations into crystallization kinetics. Recrystallization kinetics and its relationship to charge transport in poly(3-ethylhexylthiophene) (P3EHT) thin films are investigated using a combination of grazing incidence X-ray diffraction, optical absorption, and field-effect transistor measurements. These results show that thin film crystallization kinetics is limited by polymer chain reorganization and that charge percolation depends strongly on the edge-to-edge distance between aggregates. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. CuInS{sub 2} thin films obtained through the annealing of chemically deposited In{sub 2}S{sub 3}-CuS thin films

    Energy Technology Data Exchange (ETDEWEB)

    Pena, Y., E-mail: yolapm@gmail.com [Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Pedro de Alba S/N, Ciudad Universitaria, 66451, San Nicolas de los Garza, Nuevo Leon (Mexico); Lugo, S. [Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Pedro de Alba S/N, Ciudad Universitaria, 66451, San Nicolas de los Garza, Nuevo Leon (Mexico); Calixto-Rodriguez, M. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Privada Xochicalco S/N, Col Centro, 62580, Temixco, Morelos (Mexico); Vazquez, A.; Gomez, I.; Elizondo, P. [Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Pedro de Alba S/N, Ciudad Universitaria, 66451, San Nicolas de los Garza, Nuevo Leon (Mexico)

    2011-01-01

    In this work, we report the formation of CuInS{sub 2} thin films on glass substrates by heating chemically deposited multilayers of copper sulfide (CuS) and indium sulfide (In{sub 2}S{sub 3}) at 300 and 350 deg. C in nitrogen atmosphere at 10 Torr. CIS thin films were prepared by varying the CuS layer thickness in the multilayers with indium sulfide. The XRD analysis showed that the crystallographic structure of the CuInS{sub 2} (JCPDS 27-0159) is present on the deposited films. From the optical analysis it was estimated the band gap value for the CIS film (1.49 eV). The electrical conductivity varies from 3 x 10{sup -8} to 3 {Omega}{sup -1} cm{sup -1} depending on the thickness of the CuS film. CIS films showed p-type conductivity.

  13. Structural and magnetic properties of pure and Cu doped In{sub 2}O{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, N. Sai; Kaleemulla, S., E-mail: skaleemulla@gmail.com; Rao, N. Madhusudhana; Krishnamoorthi, C.; Begam, M. Rigana [Thin Films Laboratory, School of Advanced Sciences, VIT University, Vellore – 632014 (India); Amarendra, G. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam –603102 (India); UGC-DAE-CSR, Kalpakkam Node, Kokilamedu-603104 (India)

    2015-06-24

    Pure and Cu (7 at.%) doped In{sub 2}O{sub 3} thin films were prepared using an electron beam evaporation technique. A systematic study was carried out on the structural, chemical and magnetic properties of the thin films. X-ray diffraction analysis revealed that all the films were cubic in structure. The pure and Cu doped In{sub 2}O{sub 3} thin films showed ferromagnetism at room temperature. The Cu doped In{sub 2}O{sub 3} thin films showed the saturation magnetization, coercivity and retentivity of 38.71 emu/cm{sup 3}, 245 G and 5.54 emu/cm{sup 3}, respectively.

  14. Magnetoelectric coupling effect in transition metal modified polycrystalline BiFeO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sreenivas Puli, Venkata, E-mail: pvsri123@gmail.com [Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118 (United States); Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (United States); Kumar Pradhan, Dhiren [Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (United States); Gollapudi, Sreenivasulu [Department of Physics, Oakland University, Rochester, MI 48309-4401 (United States); Coondoo, Indrani [Department of Materials and Ceramic and CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Panwar, Neeraj [Department of Physics, Central University of Rajasthan, Bandar Sindri, Kishangarh 305801, Rajasthan (India); Adireddy, Shiva; Chrisey, Douglas B. [Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118 (United States); Katiyar, Ram S. [Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (United States)

    2014-11-15

    Rare-earth (Sm) and transition metal (Co) modified polycrystalline BiFeO{sub 3} (BFO) thin films have been deposited on Pt/TiO{sub 2}/SiO{sub 2}/Si substrate successfully through pulsed laser deposition (PLD) technique. Piezoelectric, leakage current and temperature dependent dielectric and magnetic behaviour were investigated for the films. Typical “butterfly-shaped” loop were observed in BSFCO films with an effective piezoelectric constant (d{sub 33}) ∼94 pm/V at 0.6 MV/cm. High dielectric constant ∼900 and low dielectric loss ∼0.25 were observed at room temperature. M–H loops have shown relatively high saturation magnetization ∼35 emu/cm{sup 3} at a maximum field of H ∼20 kOe. Enhanced magnetoelectric coupling response is observed under applied magnetic field. The multiferroic, piezoelectric, leakage current behaviours were explored. Such studies should be helpful in designing multiferroic materials based on BSFCO films. - Highlights: • Transition metal modified polycrystalline BiFeO{sub 3} thin films prepared using PLD. • High ME-coupling response was observed in co-substituted BiFeO{sub 3} thin films. • High magnetization ∼35 emu/cm{sup 3} at a maximum field of H ∼20 kOe. • Low leakage current might be due to co-substitution in BiFeO{sub 3} thin films. • A notable piezoelectric constant d{sub 33} ∼94 pm/V was found in BiFeO{sub 3} thin films.

  15. Modulation of resistive switching characteristics for individual BaTiO3 microfiber by surface oxygen vacancies

    Science.gov (United States)

    Miao, Zhilei; Chen, Lei; Zhou, Fang; Wang, Qiang

    2018-01-01

    Different from traditional thin-film BaTiO3 (BTO) RRAM device with planar structure, individual microfiber-shaped RRAM device, showing promising application potentials in the micro-sized non-volatile memory system, has not been investigated so far to demonstrate resistive switching behavior. In this work, individual sol-gel BTO microfiber has been formed using the draw-bench method, followed by annealing in different atmospheres of air and argon, respectively. The resistive switching characteristics of the individual BTO microfiber have been investigated by employing double-probe SEM measurement system, which shows great convenience to test local electrical properties by modulating the contact sites between the W probes and the BTO microfiber. For the sample annealed in air, the average resistive ON/OFF ratio is as high as 108, enhanced about four orders in comparison with the counterpart that annealed in Argon. For the sample annealed in argon ambience, the weakened resistive ON/OFF ratio can be attributed to the increased presence of oxygen vacancies in the surface of BTO fibers, and the underlying electrical conduction mechanisms are also discussed.

  16. Thickness control in electrophoretic deposition of WO{sub 3} nanofiber thin films for solar water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yuanxing; Lee, Wei Cheat; Canciani, Giacomo E.; Draper, Thomas C.; Al-Bawi, Zainab F. [Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ (United Kingdom); Bedi, Jasbir S. [School of Public Health & Zoonoses, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana 141004 Punjab (India); Perry, Christopher C. [Division of Biochemistry, School of Medicine, Loma Linda University, Loma Linda, CA 92350 (United States); Chen, Qiao, E-mail: qiao.chen@sussex.ac.uk [Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ (United Kingdom)

    2015-12-15

    Graphical abstract: - Highlights: • A novel method combining electrospinning and electrophoretic deposition was established for the creation of nanostructured semiconductor thin films. • The created thin films displayed a high chemical stability with a controllable thickness. • The PEC water splitting performance of the thin films was optimized by fine-tuning the thickness of the films. • A maximum photoconversion efficiency was achieved by 18 μm nanofibrous thin films. - Abstract: Electrophoretic deposition (EPD) of ground electrospun WO{sub 3} nanofibers was applied to create photoanodes with controlled morphology for the application of photoelectrochemical (PEC) water splitting. The correlations between deposition parameters and film thicknesses were investigated with theoretical models to precisely control the morphology of the nanostructured porous thin film. The photoconversion efficiency was further optimized as a function of film thickness. A maximum photoconversion efficiency of 0.924% from electrospun WO{sub 3} nanofibers that EPD deposited on a substrate was achieved at a film thickness of 18 μm.

  17. Microstructural properties of BaTiO{sub 3} ceramics and thin films

    Energy Technology Data Exchange (ETDEWEB)

    Fundora C, A.; Portelles, J.J.; Siqueiros, J.M. [Posgrado en Fisica de Materiales, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada. Apartado Postal 2861, 22800 Ensenada, Baja California (Mexico)

    2000-07-01

    A microstructural study of BaTiO{sub 3} ceramics obtained by the conventional ceramic method is presented. Targets were produced to grow BaTiO{sub 3} thin films by pulsed laser deposition on Pt/Ti/Si (100) substrates. X-ray diffraction, Auger Electron Spectroscopy, X-ray Photon Spectroscopy and Scanning Electron Microscopy were used to study the properties of the BaTiO{sub 3} ceramic samples and thin films, as deposited and after an annealing process. (Author)

  18. Preparation of YBa2Cu3O7-δ epitaxial thin films by pulsed ion-beam evaporation

    International Nuclear Information System (INIS)

    Sorasit, S.; Yoshida, G.; Suzuki, T.; Suematsu, H.; Jiang, W.; Yatsui, K.

    2001-01-01

    Thin films of YBa 2 Cu 3 O 7-δ (Y-123) grown epitaxially have been successfully deposited by ion-beam evaporation (IBE). The c-axis oriented YBa 2 Cu 3 O 7-δ thin films were successfully deposited on MgO and SrTiO 3 substrates. The Y-123 thin films which were prepared on the SrTiO 3 substrates were confirmed to be epitaxially grown, by X-ray diffraction analysis. The instantaneous deposition rate of the Y-123 thin films was estimated as high as 4 mm/s. (author)

  19. Magneto-optical properties of BiFeO3 thin films using surface plasmon resonance technique

    International Nuclear Information System (INIS)

    Paliwal, Ayushi; Sharma, Anjali; Tomar, Monika; Gupta, Vinay

    2014-01-01

    Indigeneously assembled surface plasmon resonance (SPR) set up has been exploited to study the magnetic field dependent optical properties of BiFeO 3 thin films. BiFeO 3 thin films have been deposited onto gold (Au) coated glass prism by using pulsed laser deposition technique. The surface plasmon modes in prism/Au/BiFeO 3 /air structure have been excited in Kretschmann configuration at the interface of Au/BiFeO 3 thin films. The SPR reflectance curves obtained for prism/Au/BiFeO 3 /air structure were utilized to investigate the optical properties of BiFeO 3 thin films at optical frequency (λ=633 nm) as a function of applied magnetic field. SPR curves shows a continuous shift towards lower angles with increasing applied magnetic field, which indicate the promising application of ferromagnetic BiFeO 3 film as a magnetic field sensor. Complex dielectric constant of deposited BiFeO 3 film was determined by fitting the experimental SPR data with Fresnel's equations. The variation of complex dielectric constant and refractive index of BiFeO 3 film was studied with increase in magnetic field, and the sensitivity of magnetic field sensor was found to be about 0.52 RIU/T

  20. Investigation of the optical property and structure of WO3 thin films with different sputtering depositions

    Science.gov (United States)

    Chen, Hsi-Chao; Jan, Der-Jun; Chen, Chien-Han; Huang, Kuo-Ting; Lo, Yen-Ming; Chen, Sheng-Hui

    2011-09-01

    The purpose of this research was to compare the optical properties and structure of tungsten oxide (WO3) thin films that was deposited by different sputtering depositions. WO3 thin films deposited by two different depositions of direct current (DC) magnetron sputtering and pulsed DC sputtering. A 99.95% WO3 target was used as the starting material for these depositions. These WO3 thin films were deposited on the ITO glass, PET and silicon substrate by different ratios of oxygen and argon. A shadow moiré interferometer would be introduced to measure the residual stress for PET substrate. RF magnetron sputtering had the large residual stress than the other's depositions. A Raman spectrum could exhibit the phase of oxidation of WO3 thin film by different depositions. At the ratio of oxygen and argon was about 1:1, and the WO3 thin films had the best oxidation. However, it was important at the change of the transmittance (ΔT = Tbleached - Tcolored) between the coloring and bleaching for the smart window. Therefore, we also found the WO3 thin films had the large variation of transmittance between the coloring and bleaching at the gas ratios of oxygen and argon of 1:1.

  1. Tungsten oxide (WO3) thin films for application in advanced energy systems

    International Nuclear Information System (INIS)

    Gullapalli, S. K.; Vemuri, R. S.; Manciu, F. S.; Enriquez, J. L.; Ramana, C. V.

    2010-01-01

    Inherent processes in coal gasification plants produce hazardous hydrogen sulfide (H 2 S), which must be continuously and efficiently detected and removed before the fuel is used for power generation. An attempt has been made in this work to fabricate tungsten oxide (WO 3 ) thin films by radio-frequency reactive magnetron-sputter deposition. The impetus being the use of WO 3 films for H 2 S sensors in coal gasification plants. The effect of growth temperature, which is varied in the range of 30-500 deg. C, on the growth and microstructure of WO 3 thin films is investigated. Characterizations made using scanning electron microscopy (SEM) and x-ray diffraction (XRD) indicate that the effect of temperature is significant on the microstructure of WO 3 films. XRD and SEM results indicate that the WO 3 films grown at room temperature are amorphous, whereas films grown at higher temperatures are nanocrystalline. The average grain-size increases with increasing temperature. WO 3 films exhibit smooth morphology at growth temperatures ≤300 deg. C while relatively rough at >300 deg. C. The analyses indicate that the nanocrystalline WO 3 films grown at 100-300 deg. C could be the potential candidates for H 2 S sensor development for application in coal gasification systems.

  2. Effect of Sb content on the thermoelectric properties of annealed CoSb_3 thin films deposited via RF co-sputtering

    International Nuclear Information System (INIS)

    Ahmed, Aziz; Han, Seungwoo

    2017-01-01

    Graphical abstract: The X-ray diffraction patterns and temperature dependence of the Seebeck coefficient of the annealed Co–Sb thin films. - Highlights: • CoSb_3 phase thin films were prepared using RF co sputtering method. • Thin film thermoelectric properties were hugely dependent on Sb content. • All thin films shows n-type conduction behavior at high temperatures. • The thin films with excess Sb possess the largest Seebeck coefficient. • The thin films with CoSb_2 phase possess the largest power factor. - Abstract: A series of CoSb_3 thin films with Sb contents in the range 70–79 at.% were deposited at room temperature via RF co-sputtering. The thin films were amorphous in the as-deposited state and annealed at 300 °C for 3 h to obtain crystalline samples. The annealed thin films were characterized using scanning electron microscopy and X-ray diffraction (XRD), and these data indicate that the films exhibited good crystallinity. The XRD patterns indicate single-phase CoSb_3 thin films in the Sb-rich samples. For the Sb-deficient samples, however, mixed-phase thin films consisting of CoSb_2 and CoSb_3 components were obtained. The electrical and thermoelectric properties were measured at temperatures up to 760 K and found to be highly sensitive to the phases that were present. We observed a change in the thermoelectric properties of the films from p-type at low temperatures to n-type at high temperatures, which indicates potential applications as n-type thermoelectric thin films. A large Seebeck coefficient and power factor was obtained for the single-phase CoSb_3 thin films. The CoSb_2 phase thin films were also found to possess a significant Seebeck coefficient, which coupled with the much smaller electrical resistivity, provided a larger power factor than the single-phase CoSb_3 thin films. We report maximum power factor of 7.92 mW/m K"2 for the CoSb_2-containing mixed phase thin film and 1.26 mW/m K"2 for the stoichiometric CoSb_3 thin film.

  3. Evaluation of space environmental effects on metals and optical thin films on EOIM-3

    Energy Technology Data Exchange (ETDEWEB)

    Vaughn, J.A.; Linton, R.C.; Finckenor, M.M.; Kamenetzky, R.R.

    1995-02-01

    Metals and optical thin films exposed to the space environment on the Third Flight of the Evaluation of Oxygen Interactions with Materials (EOIM-3) payload, onboard Space Shuttle mission STS-46 were evaluated. The materials effects described in this paper include the effects of space exposure on various pure metals, optical thin films, and optical thin film metals. The changes induced by exposure to the space environment in the material properties were evaluated using bidirectional reflectance distribution function (BRDF), specular reflectance (250 nm to 2500 nm), ESCA, VUV reflectance (120 nm to 200 nm), ellipsometry, FTIR and optical properties. Using these analysis techniques gold optically thin film metal mirrors with nickel undercoats were observed to darken due to nickel diffusion through the gold to the surface. Also, thin film nickel mirrors formed nickel oxide due to exposure to both the atmosphere and space.

  4. Evaluation of space environmental effects on metals and optical thin films on EOIM-3

    Science.gov (United States)

    Vaughn, Jason A.; Linton, Roger C.; Finckenor, Miria M.; Kamenetzky, Rachel R.

    1995-01-01

    Metals and optical thin films exposed to the space environment on the Third Flight of the Evaluation of Oxygen Interactions with Materials (EOIM-3) payload, onboard Space Shuttle mission STS-46 were evaluated. The materials effects described in this paper include the effects of space exposure on various pure metals, optical thin films, and optical thin film metals. The changes induced by exposure to the space environment in the material properties were evaluated using bidirectional reflectance distribution function (BRDF), specular reflectance (250 nm to 2500 nm), ESCA, VUV reflectance (120 nm to 200 nm), ellipsometry, FTIR and optical properties. Using these analysis techniques gold optically thin film metal mirrors with nickel undercoats were observed to darken due to nickel diffusion through the gold to the surface. Also, thin film nickel mirrors formed nickel oxide due to exposure to both the atmosphere and space.

  5. Leakage current behavior in lead-free ferroelectric (K,Na)NbO3-LiTaO3-LiSbO3 thin films

    Science.gov (United States)

    Abazari, M.; Safari, A.

    2010-12-01

    Conduction mechanisms in epitaxial (001)-oriented pure and 1 mol % Mn-doped (K0.44,Na0.52,Li0.04)(Nb0.84,Ta0.1,Sb0.06)O3 (KNN-LT-LS) thin films on SrTiO3 substrate were investigated. Temperature dependence of leakage current density was measured as a function of applied electric field in the range of 200-380 K. It was shown that the different transport mechanisms dominate in pure and Mn-doped thin films. In pure (KNN-LT-LS) thin films, Poole-Frenkel emission was found to be responsible for the leakage, while Schottky emission was the dominant mechanism in Mn-doped thin films at higher electric fields. This is a remarkable yet clear indication of effect of 1 mol % Mn on the resistive behavior of such thin films.

  6. Thin Film Microbatteries

    International Nuclear Information System (INIS)

    Dudney, Nancy J.

    2008-01-01

    aerosol spray coating, for one or more components of the battery. The active materials used for the thin film cathodes and anodes are familiar intercalation compounds, but the microstructures and often the cycling properties of the thin films may be quite distinct from those of battery electrodes formed from powders. The thin film cathodes are dense and homogeneous with no added phases such as binders or electrolytes. When deposited at ambient temperatures, the films of cathodes, such as LiCoO 2 , V 2 O 5 , LiMn 2 O4 , LiFePO 4 are amorphous or nanocrystalline. But even in this form, they often act as excellent cathodes with large specific capacities and good stability for hundreds to thousands of cycles. Annealing the cathode films at temperatures of 300 to 800 C may be used to induce crystallization and grain growth of the desired intercalation compound. Crystallizing the cathode film generally improves the Li chemical diffusivity in the electrode material, and hence the power delivered by the battery, by 1-2 orders of magnitude. The microstructure is also tailored by the deposition and heat treatment. Figure 3 shows a fracture edge of an annealed LiCoO 2 cathode film on an alumina substrate. The columnar microstructure, which is typical of a vapor deposited film, sinters at high temperatures leaving small fissures between the dense columns. Such crystalline films also may have a preferred crystallographic orientation. For LiCoO 2 films the crystallographic texture differs for films deposited by sputtering versus pulse laser ablation processes. To improve the manufacturability of the thin film batteries, it would be beneficial to eliminate or minimize the temperature or duration of the annealing step. Several efforts have lead to low temperature fabrication of thin film batteries on polyimide substrates, but the battery capacity and rate are lower than those treated at high temperatures. For the battery anode, many designs use a vapor-deposited metallic lithium film as

  7. Neuromorphic transistor achieved by redox reaction of WO3 thin film

    Science.gov (United States)

    Tsuchiya, Takashi; Jayabalan, Manikandan; Kawamura, Kinya; Takayanagi, Makoto; Higuchi, Tohru; Jayavel, Ramasamy; Terabe, Kazuya

    2018-04-01

    An all-solid-state neuromorphic transistor composed of a WO3 thin film and a proton-conducting electrolyte was fabricated for application to next-generation information and communication technology including artificial neural networks. The drain current exhibited a 4-order-of-magnitude increment by redox reaction of the WO3 thin film owing to proton migration. Learning and forgetting characteristics were well tuned by the gate control of WO3 redox reactions owing to the separation of the current reading path and pulse application path in the transistor structure. This technique should lead to the development of versatile and low-power-consumption neuromorphic devices.

  8. Magnetic behavior of La2/3Ca1/3MnO3 / BaTiO3 bilayers

    Science.gov (United States)

    Ordonez, John E.; Gomez, Maria E.; Lopera, Wilson; Marin, Lorena; Pardo, Jose A.; Morellon, Luis; Algarabel, Pedro; Prieto, Pedro

    2013-03-01

    We have grown ferroelectric BaTiO3(BTO) and ferromagnetic La2/3Ca1/3MnO3 (LCMO) onto (001) SrTiO3 and Nb:SrTiO3 by pulsed laser deposition (PLD) at pure oxygen atmosphere, and a substrate temperature of 820° C, seeking for a multiferroic behavior in this structure. From x-ray diffraction (XRD) we found lattice parameter aBTO=4.068 Å, and aLCMO=3.804 Å, for each individual layer. In the BTO/LCMO bilayer, (002)-Bragg peak for BTO maintain its position whereas (002) LCMO peak shift to lower Bragg angle indicating a strained LCMO film. Magnetization measurements reveal an increase in the Curie temperature from 170 K to 220 K for the bilayer when LCMO (t = 47 nm) is deposited on BTO (t=52 nm) film, while depositing the BTO (50 nm) above LCMO (48 nm) the Curie temperature remains at values close to that obtained for a LCMO single layer (~175 K), deposited under identical growth parameters This work has been supported by Instituto de Nanociencias de Aragón, Zaragoza, Spain, ``El Patrimonio Autónomo Fondo Nacional de Financiamiento para CT&I FJC'' COLCIENCIAS-CENM Contract RC 275-2011 and Research Project COLCIENCIAS-UNIVALLE.

  9. Synthesis of BaTiO3 powder from barium titanyl oxalate (BTO ...

    Indian Academy of Sciences (India)

    Unknown

    the synthesis of BaTiO3 from the mixture of barium car- bonate and titanium dioxide employing microwave heat- ing. They observed that hypostoichiometric TiO2 (TiO2–x) reacted with BaCO3 in the presence of microwave field at temperature as low as 350°C to give the mixture of hexa- gonal and tetragonal forms of BaTiO3 ...

  10. 3D visualization of the internal nanostructure of polyamide thin films in RO membranes

    KAUST Repository

    Pacheco Oreamuno, Federico

    2015-11-02

    The front and back surfaces of fully aromatic polyamide thin films isolated from reverse osmosis (RO) membranes were characterized by TEM, SEM and AFM. The front surfaces were relatively rough showing polyamide protuberances of different sizes and shapes; the back surfaces were all consistently smoother with very similar granular textures formed by polyamide nodules of 20–50 nm. Occasional pore openings of approximately the same size as the nodules were observed on the back surfaces. Because traditional microscopic imaging techniques provide limited information about the internal morphology of the thin films, TEM tomography was used to create detailed 3D visualizations that allowed the examination of any section of the thin film volume. These tomograms confirmed the existence of numerous voids within the thin films and revealed structural characteristics that support the water permeance difference between brackish water (BWRO) and seawater (SWRO) RO membranes. Consistent with a higher water permeance, the thin film of the BWRO membrane ESPA3 contained relatively more voids and thinner sections of polyamide than the SWRO membrane SWC3. According to the tomograms, most voids originate near the back surface and many extend all the way to the front surface shaping the polyamide protuberances. Although it is possible for the internal voids to be connected to the outside through the pore openings on the back surface, it was verified that some of these voids comprise nanobubbles that are completely encapsulated by polyamide. TEM tomography is a powerful technique for investigating the internal nanostructure of polyamide thin films. A comprehensive knowledge of the nanostructural distribution of voids and polyamide sections within the thin film may lead to a better understanding of mass transport and rejection mechanisms in RO membranes.

  11. 3D visualization of the internal nanostructure of polyamide thin films in RO membranes

    KAUST Repository

    Pacheco Oreamuno, Federico; Sougrat, Rachid; Reinhard, Martin; Leckie, James O.; Pinnau, Ingo

    2015-01-01

    The front and back surfaces of fully aromatic polyamide thin films isolated from reverse osmosis (RO) membranes were characterized by TEM, SEM and AFM. The front surfaces were relatively rough showing polyamide protuberances of different sizes and shapes; the back surfaces were all consistently smoother with very similar granular textures formed by polyamide nodules of 20–50 nm. Occasional pore openings of approximately the same size as the nodules were observed on the back surfaces. Because traditional microscopic imaging techniques provide limited information about the internal morphology of the thin films, TEM tomography was used to create detailed 3D visualizations that allowed the examination of any section of the thin film volume. These tomograms confirmed the existence of numerous voids within the thin films and revealed structural characteristics that support the water permeance difference between brackish water (BWRO) and seawater (SWRO) RO membranes. Consistent with a higher water permeance, the thin film of the BWRO membrane ESPA3 contained relatively more voids and thinner sections of polyamide than the SWRO membrane SWC3. According to the tomograms, most voids originate near the back surface and many extend all the way to the front surface shaping the polyamide protuberances. Although it is possible for the internal voids to be connected to the outside through the pore openings on the back surface, it was verified that some of these voids comprise nanobubbles that are completely encapsulated by polyamide. TEM tomography is a powerful technique for investigating the internal nanostructure of polyamide thin films. A comprehensive knowledge of the nanostructural distribution of voids and polyamide sections within the thin film may lead to a better understanding of mass transport and rejection mechanisms in RO membranes.

  12. Room temperature deposition of perpendicular magnetic anisotropic Co{sub 3}Pt thin films on glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu-Shen; Dai, Hong-Yu; Hsu, Yi-Wei [Department of Chemical Engineering and Materials Science, Yuan-Ze University, Chung-Li 32003, Taiwan (China); Ou, Sin-Liang, E-mail: slo@mail.dyu.edu.tw [Department of Materials Science and Engineering, Da-Yeh University, Changhua 51591, Taiwan (China); Chen, Shi-Wei [National Synchrotron Radiation Research Center (NSRRC), Hsinchu 300, Taiwan (China); Lu, Hsi-Chuan; Wang, Sea-Fue [Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei 106, Taiwan (China); Sun, An-Cheng, E-mail: acsun@saturn.yzu.edu.tw [Department of Chemical Engineering and Materials Science, Yuan-Ze University, Chung-Li 32003, Taiwan (China)

    2017-03-01

    Co{sub 3}Pt alloy thin films were deposited on the glass substrate at room temperature (RT) and 300 °C, which showed high perpendicular magnetic anisotropy (PMA) and isotropy magnetic behaviors, respectively. Co{sub 3}Pt HCP (0002) planes grew along the substrate plane for the films deposited at RT. The easy axis [0001] was consequently vertical to the substrate surface and obtained the predominant PMA. Large magnetic domains and sharp boundary also supported high PMA in RT-deposited samples. On the other hand, the PMA was significantly decreased with increasing the deposition temperature from RT to 300 °C. Hard HCP(0002) and soft A1(111) co-existed in the film and the magnetic exchanged coupling between these two phases induced isotropy magnetic behavior. In addition, the various thicknesses (t) of the RT-deposited Co{sub 3}Pt films were deposited with different base pressures prior to sputtering. The Kerr rotation loops showed high PMA and out-of-plane squareness (S{sub ⊥}) of ~0.9 were found in low base pressure chamber. Within high base pressure chamber, Co{sub 3}Pt films just show magnetic isotropy behaviors. This study provides a fabrication method for the preparation of high PMA HCP-type Co{sub 3}Pt films on the glass substrate without any underlayer at RT. The results could be the base for future development of RT-deposited magnetic alloy thin film with high PMA. - Highlights: • Fabricated high perpendicular magnetic anisotropy Co{sub 3}Pt thin film on glass substrate. • Prepared HCP Co{sub 3}Pt thin film at room temperature. • The key to enhance the PMA of the Co{sub 3}Pt films. • Thinner film is good to fabricate PMA Co{sub 3}Pt thin films.

  13. Investigation of water content in electrolyte solution on electrochromic properties of WO3 thin Films

    Directory of Open Access Journals (Sweden)

    Zahra Abadi

    2017-05-01

    Full Text Available Tungsten oxide thin films were prepared by a cathodic electrodeposition method at -0.450 mV in order to investigate how water content affects their electrochromic properties. FESEM images exhibit that WO3 thin films consist of 65 nm uniform grains. Thin Films were electrochemically investigated in 0.1M LiClO4 in propylene carbonate electrolyte with and without 5vol% water content by cyclic voltammetry and chronoamperometry. The results indicate that tungsten oxide thin films exhibit faster switching time between coloration and bleaching states and also higher coloration efficiency in hydrated electrolyte.  

  14. Thin-film photovoltaic technology

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, R.N. [National Renewable Energy Laboratory, Golden, CO (United States)

    2010-07-01

    The high material and processing costs associated with single-crystal and polycrystalline silicon wafers that are commonly used in photovoltaic cells render these modules expensive. This presentation described thin-film solar cell technology as a promising alternative to silicon solar cell technology. Cadmium telluride (CdTe) thin films along with copper, indium, gallium, and selenium (CIGS) thin films have become the leaders in this field. Their large optical absorption coefficient can be attributed to a direct energy gap that allows the use of thin layers (1-2 {mu}m) of active material. The efficiency of thin-film solar cell devices based on CIGS is 20 per cent, compared to 16.7 per cent for thin-film solar cell devices based on CdTe. IBM recently reported an efficiency of 9.7 per cent for a new type of inorganic thin-film solar cell based on a Cu{sub 2}ZnSn(S, Se){sub 4} compound. The efficiency of an organic thin-film solar cell is 7.9 per cent. This presentation included a graph of PV device efficiencies and discussed technological advances in non-vacuum deposited, CIGS-based thin-film solar cells. 1 fig.

  15. Dielectric properties of electron irradiated PbZrO 3 thin films

    Indian Academy of Sciences (India)

    The present paper deals with the study of the effects of electron (8 MeV) irradiation on the dielectric and ferroelectric properties of PbZrO3 thin films grown by sol–gel technique. The films were (0.62 m thick) subjected to electron irradiation using Microtron accelerator (delivered dose 80, 100, 120 kGy). The films were well ...

  16. Photoelectrochemical properties of In{sub 2}Se{sub 3} thin films: Effect of substrate temperature

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Abhijit A., E-mail: aay_physics@yahoo.co.in [Thin Film Physics Laboratory, Department of Physics, Electronics and Photonics, Rajarshi Shahu Mahavidyalaya, Latur, M.S. 413512 (India); Salunke, S.D. [Department of Chemistry and Analytical Chemistry, Rajarshi Shahu Mahavidyalaya, Latur, M.S. 413512 (India)

    2015-08-15

    Highlights: • Photoelectrochemical properties of In{sub 2}Se{sub 3} thin films. • In{sub 2}Se{sub 3} films are of n-type with I{sub sc} and V{sub oc} of 1.05 mA/cm{sup 2} and 261 mV respectively. • Efficiency (η) and fill factor (FF) is found to be 0.71% and 0.51% respectively. • Performance of cell can motivate further studies concerning solar energy conversion. - Abstract: In{sub 2}Se{sub 3} thin films have been deposited onto fluorine doped tin oxide coated (FTO) glass substrates at various substrate temperatures by spray pyrolysis. The photoelectrochemical cell configurations were In{sub 2}Se{sub 3} thin film/1 M (NaOH + Na{sub 2}S + S)/C. From capacitance–voltage (C–V) and current–voltage (I–V) characteristics; it is concluded that In{sub 2}Se{sub 3} thin films are of n-type. The Fill factor (FF) and solar conversion efficiency (η) were calculated from photovoltaic power output characteristics. In this instance, the highest measured photocurrent density of 1.05 mA/cm{sup 2} and open circuit voltage of 261 mV is observed for film deposited at 350 °C resulting in maximum power conversion efficiency (η) and fill factor (FF) to be 0.71% and 0.51% respectively. Electrochemical impedance spectroscopy study shows that the In{sub 2}Se{sub 3} film deposited at 350 °C shows better performance in photoelectrochemical cell. The performance of indium selenide thin film observed in our work can motivate further studies concerning solar energy conversion.

  17. Thin film processes II

    CERN Document Server

    Kern, Werner

    1991-01-01

    This sequel to the 1978 classic, Thin Film Processes, gives a clear, practical exposition of important thin film deposition and etching processes that have not yet been adequately reviewed. It discusses selected processes in tutorial overviews with implementation guide lines and an introduction to the literature. Though edited to stand alone, when taken together, Thin Film Processes II and its predecessor present a thorough grounding in modern thin film techniques.Key Features* Provides an all-new sequel to the 1978 classic, Thin Film Processes* Introduces new topics, and sever

  18. Effect of Sb content on the thermoelectric properties of annealed CoSb{sub 3} thin films deposited via RF co-sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Aziz, E-mail: aziz_ahmed@ust.ac.kr [Department of Nano-Mechatronics, Korea University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, 305-350 (Korea, Republic of); Department of Nano-Mechanics, Korea Institute of Machinery and Materials (KIMM), 156 Gajeongbuk-ro, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of); Han, Seungwoo, E-mail: swhan@kimm.re.kr [Department of Nano-Mechatronics, Korea University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, 305-350 (Korea, Republic of); Department of Nano-Mechanics, Korea Institute of Machinery and Materials (KIMM), 156 Gajeongbuk-ro, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of)

    2017-06-30

    Graphical abstract: The X-ray diffraction patterns and temperature dependence of the Seebeck coefficient of the annealed Co–Sb thin films. - Highlights: • CoSb{sub 3} phase thin films were prepared using RF co sputtering method. • Thin film thermoelectric properties were hugely dependent on Sb content. • All thin films shows n-type conduction behavior at high temperatures. • The thin films with excess Sb possess the largest Seebeck coefficient. • The thin films with CoSb{sub 2} phase possess the largest power factor. - Abstract: A series of CoSb{sub 3} thin films with Sb contents in the range 70–79 at.% were deposited at room temperature via RF co-sputtering. The thin films were amorphous in the as-deposited state and annealed at 300 °C for 3 h to obtain crystalline samples. The annealed thin films were characterized using scanning electron microscopy and X-ray diffraction (XRD), and these data indicate that the films exhibited good crystallinity. The XRD patterns indicate single-phase CoSb{sub 3} thin films in the Sb-rich samples. For the Sb-deficient samples, however, mixed-phase thin films consisting of CoSb{sub 2} and CoSb{sub 3} components were obtained. The electrical and thermoelectric properties were measured at temperatures up to 760 K and found to be highly sensitive to the phases that were present. We observed a change in the thermoelectric properties of the films from p-type at low temperatures to n-type at high temperatures, which indicates potential applications as n-type thermoelectric thin films. A large Seebeck coefficient and power factor was obtained for the single-phase CoSb{sub 3} thin films. The CoSb{sub 2} phase thin films were also found to possess a significant Seebeck coefficient, which coupled with the much smaller electrical resistivity, provided a larger power factor than the single-phase CoSb{sub 3} thin films. We report maximum power factor of 7.92 mW/m K{sup 2} for the CoSb{sub 2}-containing mixed phase thin film and 1

  19. Synthesis of flower-like BaTiO3/Fe3O4 hierarchically structured particles and their electrorheological and magnetic properties.

    Science.gov (United States)

    Wang, Baoxiang; Yin, Yichao; Liu, Chenjie; Yu, Shoushan; Chen, Kezheng

    2013-07-21

    Flower-like BaTiO3/Fe3O4 hierarchically structured particles composed of nano-scale structures on micro-scale materials were synthesized by a simple solvothermal approach and characterized by the means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), magnetic testing and rotary viscometer. The influences on the morphology and structure of solvothermal times, type and amount of surfactant, EG : H2O ratio, etc. were studied. Magnetic testing results show that the samples have strong magnetism and they exhibit superparamagnetic behavior, as evidenced by no coercivity and the remanence at room temperature, due to their very small sizes, observed on the M-H loop. The saturation magnetization (M(s)) value can achieve 18.3 emu g(-1). The electrorheological (ER) effect was investigated using a suspension of the flower-like BaTiO3/Fe3O4 hierarchically structured particles dispersed in silicone oil. We can observe a slight shear-thinning behavior of shear viscosity at a low shear rate region even at zero applied electric field and a Newtonian fluid behavior at high shear rate regions.

  20. Crystallized InBiS3 thin films with enhanced optoelectronic properties

    Science.gov (United States)

    Ali, N.; Hussain, Arshad; Ahmed, R.; Omar, M. Firdaus Bin; Sultan, M.; Fu, Yong Qing

    2018-04-01

    In this paper, a one-step thermal evaporation approach was used for fabrication of indium bismuth sulphide thin films, and the synergetic effects of co-evaporation of two sources (indium granules and Bi2S3 powders) were investigated using different characterization techniques. X-ray diffraction (XRD) analysis confirmed the crystalline orthorhombic structure for the post-annealed samples. Surface roughness and crystal size of the obtained film samples were increased with increasing annealing temperatures. Analysis using X-ray photoelectron spectroscopy showed the formation of the InBiS3 structure for the obtained films, which is also confirmed by the XRD results. The optical absorption coefficient value of the annealed samples was found to be in the order of 105 cm-1 in the visible region of the solar spectrum. The optical band gap energy and electrical resistivity of the fabricated samples were observed to decrease (from 2.2 to 1.3 eV, and from 0.3 to 0.01 Ω-cm, respectively) with increasing annealing temperatures (from 200 to 350 °C), indicating the suitability of the prepared InBiS3 thin films for solar cell applications.

  1. Thin film bismuth iron oxides useful for piezoelectric devices

    Science.gov (United States)

    Zeches, Robert J.; Martin, Lane W.; Ramesh, Ramamoorthy

    2016-05-31

    The present invention provides for a composition comprising a thin film of BiFeO.sub.3 having a thickness ranging from 20 nm to 300 nm, a first electrode in contact with the BiFeO.sub.3 thin film, and a second electrode in contact with the BiFeO.sub.3 thin film; wherein the first and second electrodes are in electrical communication. The composition is free or essentially free of lead (Pb). The BFO thin film is has the piezoelectric property of changing its volume and/or shape when an electric field is applied to the BFO thin film.

  2. Preparation of Pb(Zr, Ti)O3 Thin Films by Plasma-Assisted Sputtering

    Science.gov (United States)

    Hioki, Tsuyoshi; Akiyama, Masahiko; Ueda, Tomomasa; Onozuka, Yutaka; Suzuki, Kouji

    1999-09-01

    A novel plasma-assisted RF magnetron sputtering system with an immersed coil antenna between a target and a substrate was applied for preparing Pb(Zr, Ti)O3 (PZT) thin films. The antenna enabled the generation of inductively coupled plasma (ICP) independently of the target RF source. The plasma assisted by the antenna resulted in the changes of ion fluxes and these energy distributions irradiating to the substrate. The crystalline phase of the deposited PZT thin films was occupied by the perovskite phase depending on the antenna power. In addition, a high deposition rate, modified uniformity of film thickness, and a dense film structure with large columnar grains were obtained as a result of effects of the assisted plasma. The application of the plasma-assisted sputtering method may enable the preparation of PZT thin films that haveexcellent properties.

  3. Positron annihilation lifetime study of positive temperature coefficient BaTiO3 samples

    International Nuclear Information System (INIS)

    Ling Chen; Mingkang Teng; Guanghou Wang; Xiaoyun Li; Tianchang Lu

    1989-01-01

    In order to investigate the doped vacancies in BaTiO 3 samples as well as their influence on the positive temperature coefficient (PTC) the positron annihilation lifetime spectroscopy was applied. Two groups of BaTiO 3 samples with BaO excess were prepared by doping different concentrations of La 2 O 3 and Nb 2 O 5 , respectively in the range from 0.1 to 3 at%. A third group of samples of two Sb-doped PTC BaTiO 3 semiconductors with excess BaO or TiO 2 were studied by the aid of positron technique before and after being reduced. It is shown that the positron lifetime parameters are sensitive to changes in the vacancy concentration in BaTiO 3 ceramics near the 0.1 mol% region. But they are almost unchanged during reduction processing; the resistivity of samples changed by one to two orders of magnitude through the reduction. It can be concluded that the PTC effect is due to oxygen on the grain boundary rather than vacancies, and that the Heywang-Jonker model is more reasonable

  4. Infrared refractive index of thin YBa2Cu3O7 superconducting films

    International Nuclear Information System (INIS)

    Zhang, Z.M.; Choi, B.I.; Le, T.A.; Flik, M.I.; Siegal, M.P.; Phillips, J.M.

    1992-01-01

    This work investigates whether thin-film optics with a constant refractive index can be applied to high-T c superconducting thin films. The reflectance and transmittance of YBa 2 Cu 3 O 7 films on LaAlO 3 substrates are measured using a Fourier-transform infrared spectrometer at wavelengths from 1 to 100 μm at room temperature. The reflectance of these superconducting films at 10K in the wavelength region from 2.5 to 25 μm is measured using a cryogenic reflectance accessory. The film thickness varies from 10 to 200 nm. By modeling the frequency-dependent complex conductivity in the normal and superconducting states and applying electromagnetic-wave theory, the complex refractive index of YBa 2 Cu 3 O 7 films is obtained with a fitting technique. It is found that a thickness-independent refractive index can be applied even to a 25nm film, and average values of the spectral refractive index for film thicknesses between 25 and 200 nm are recommended for engineering applications

  5. Growth and giant coercive field of spinel-structured Co3- x Mn x O4 thin films

    Science.gov (United States)

    Kwak, Yongsu; Song, Jonghyun; Koo, Taeyeong

    2016-08-01

    We grew epitaxial thin films of CoMn2O4 and Co2MnO4 on Nb-doped SrTiO3(011) and SrTiO3(001) single crystal substrates using pulsed laser deposition. The magnetic Curie temperature ( T c ) of the Co2MnO4 thin films was ~176 K, which is higher than that of the bulk whereas CoMn2O4 thin films exhibited a value of T c (~151 K) lower than that of the bulk. For the Co2MnO4 thin films, the M - H loop showed a coercive field of ~0.7 T at 10 K, similar to the value for the bulk. However, the M -H loop of the CoMn2O4(0 ll) thin film grown on a Nb-doped SrTiO3(011) substrate exhibited a coercive field of ~4.5 T at 30 K, which is significantly higher than those of the Co2MnO4 thin film and bulk. This giant coercive field, only observed for the CoMn2O4(0 ll) thin film, can be attributed to the shape anisotropy and strong spin-orbit coupling.

  6. Diffusivity, solubility and thermodynamic modelling of diffusion growth of Ga"3"+-doped LiTaO_3 thin film for integrated optics

    International Nuclear Information System (INIS)

    Zhang, De-Long; Zhang, Qun; Zhang, Pei; Kang, Jian; Wong, Wing-Han; Yu, Dao-Yin

    2016-01-01

    Graphical abstract: Diffusion growth of Ga"3"+-doped LiTaO_3(LT) thin film was studied thermodynamically. Some Ga"3"+-doped LT thin films were grown on LT surface by in-diffusion of homogeneously coated Ga_2O_3 film at the temperature range of (1273 to 1473) K. The Ga"3"+ profile in the grown thin film was analyzed by secondary ion mass spectrometry. Form the measured Ga"3"+ profiles, some thermodynamic parameters were obtained. These include diffusivity, diffusion constant, chemical activation energy, solubility, solubility constant and enthalpy of solution. These parameters are crucial to design and growth of a Ga"3"+-doped LT thin film with desired Ga"3"+ profile for integrated optics application. A thermodynamic model is suggested for the growth and verified experimentally. - Highlights: • Diffusion growth of Ga"3"+-doped LiTaO_3 thin film were studied thermodynamically. • Diffusion constant is 1.41 · 10"−"6 m"2/s and activation energy is 237.2 kJ/mol. • Solubility constant is 22.9 · 10"2"6 ions/m"3 and enthalpy of solution is 28.9 kJ/mol. • Ga"3"+ dopant has small effect on LiTaO_3 refractive index. • Ga"3"+ growth can be described by a Fick-type equation with a constant diffusivity. - Abstract: A thermodynamic study was performed on diffusion growth of Ga"3"+-doped LiTaO_3(LT) thin film for integrated optics. Some Ga"3"+-doped LT thin films were grown on LT surface by in-diffusion of homogeneously coated Ga_2O_3 film at the temperature range of (1273 to 1473) K. After growth, the refractive indices at Ga"3"+-doped and un-doped surface parts were measured by prism coupling technique and Li composition there was evaluated from the measured refractive indices. The results show that Ga"3"+ dopant has small effect on the LT index. Li_2O out-diffusion is not measurable. The Ga"3"+ profile in the grown thin film was analysed by secondary ion mass spectrometry. It is found that the grown Ga"3"+ ions follow a complementary error function profile. A

  7. Structure and magnetic properties of Fe doped In{sub 2}O{sub 3} thin films prepared by electron beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, N. Sai; Kaleemulla, S., E-mail: skaleemulla@gmail.com; Rao, N. Madhusudhana; Krishnamoorthi, C.; Begam, M. Rigana [Thin Films Laboratory, School of Advanced Sciences, VIT University, Vellore – 632014 (India); Amarendra, G. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603102 (India); UGC-DAE-CSR, Kalpakkam Node, Kokilamedu, Tamilnadu -603104 (India)

    2015-06-24

    Pure and Fe (7 at.%) doped In{sub 2}O{sub 3} thin films were grown onto the glass substrates by electron beam evaporation technique. The structural and magnetic properties of the pure and Fe doped In{sub 2}O{sub 3} thin films have been studied. The undoped and Fe doped In{sub 2}O{sub 3} thin films shown ferromagnetic property at room temperature. A magnetization of 24 emu/cm{sup 3} was observed for pure In{sub 2}O{sub 3} thin films. The magnetization of 38.23 emu/cm{sup 3} was observed for the Fe (7 at.%) doped In{sub 2}O{sub 3} thin films.

  8. Influence of film thickness and Fe doping on LPG sensing properties of Mn3O4 thin film grown by SILAR method

    Science.gov (United States)

    Belkhedkar, M. R.; Ubale, A. U.

    2018-05-01

    Nanocrystalline Fe doped and undoped Mn3O4 thin films have been deposited by Successive Ionic Layer Adsorption and Reaction (SILAR) method onto glass substrates using MnCl2 and NaOH as cationic and anionic precursors. The grazing incidence X-ray diffraction (GIXRD) and field emission scanning electron microscopy (FESEM)) have been carried out to analyze structural and surface morphological properties of the films. The LPG sensing performance of Mn3O4thin films have been studied by varying temperature, concentration of LPG, thickness of the film and doping percentage of Fe. The LPG response of the Mn3O4thin films were found to be enhances with film thickness and decreases with increased Fe doping (0 to 8 wt. %) at 573 K temperature.

  9. Dielectric properties of DC reactive magnetron sputtered Al{sub 2}O{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Prasanna, S. [Thin Film Center, Department of Physics, PSG College of Technology, Coimbatore, 641 004 (India); Mohan Rao, G. [Department of Instrumentation, Indian Institute of Science (IISc), Bangalore, 560 012 (India); Jayakumar, S., E-mail: s_jayakumar_99@yahoo.com [Thin Film Center, Department of Physics, PSG College of Technology, Coimbatore, 641 004 (India); Kannan, M.D. [Thin Film Center, Department of Physics, PSG College of Technology, Coimbatore, 641 004 (India); Ganesan, V. [Low Temperature Lab, UGC-DAE Consortium for Scientific Research (CSR), Indore, 452 017 (India)

    2012-01-31

    Alumina (Al{sub 2}O{sub 3}) thin films were sputter deposited over well-cleaned glass and Si < 100 > substrates by DC reactive magnetron sputtering under various oxygen gas pressures and sputtering powers. The composition of the films was analyzed by X-ray photoelectron spectroscopy and an optimal O/Al atomic ratio of 1.59 was obtained at a reactive gas pressure of 0.03 Pa and sputtering power of 70 W. X-ray diffraction results revealed that the films were amorphous until 550 Degree-Sign C. The surface morphology of the films was studied using scanning electron microscopy and the as-deposited films were found to be smooth. The topography of the as-deposited and annealed films was analyzed by atomic force microscopy and a progressive increase in the rms roughness of the films from 3.2 nm to 4.53 nm was also observed with increase in the annealing temperature. Al-Al{sub 2}O{sub 3}-Al thin film capacitors were then fabricated on glass substrates to study the effect of temperature and frequency on the dielectric property of the films. Temperature coefficient of capacitance, AC conductivity and activation energy were determined and the results are discussed. - Highlights: Black-Right-Pointing-Pointer Al{sub 2}O{sub 3} thin films were deposited by DC reactive magnetron sputtering. Black-Right-Pointing-Pointer The films were found to be amorphous up to annealing temperature of 550 C. Black-Right-Pointing-Pointer An increase in rms roughness of the films was observed with annealing. Black-Right-Pointing-Pointer Al-Al{sub 2}O{sub 3}-Al thin film capacitors were fabricated and dielectric constant was 7.5. Black-Right-Pointing-Pointer The activation energy decreased with increase in frequency.

  10. LPCVD homoepitaxy of Si doped β-Ga2O3 thin films on (010) and (001) substrates

    Science.gov (United States)

    Rafique, Subrina; Karim, Md Rezaul; Johnson, Jared M.; Hwang, Jinwoo; Zhao, Hongping

    2018-01-01

    This paper presents the homoepitaxy of Si-doped β-Ga2O3 thin films on semi-insulating (010) and (001) Ga2O3 substrates via low pressure chemical vapor deposition with a growth rate of ≥1 μm/h. Both high resolution scanning transmission electron microscopy and X-ray diffraction measurements demonstrated high crystalline quality homoepitaxial growth of these thin films. Atomic resolution STEM images of the as-grown β-Ga2O3 thin films on (010) and (001) substrates show high quality material without extended defects or dislocations. The charge carrier transport properties of the as-grown Si-doped β-Ga2O3 thin films were characterized by the temperature dependent Hall measurement using van der Pauw patterns. The room temperature carrier concentrations achieved for the (010) and (001) homoepitaxial thin films were ˜1.2 × 1018 cm-3 and ˜9.5 × 1017 cm-3 with mobilities of ˜72 cm2/V s and ˜42 cm2/V s, respectively.

  11. Growth and structural properties of indium sesquitelluride (In2Te3) thin films

    International Nuclear Information System (INIS)

    Desai, R.R.; Lakshminarayana, D.; Patel, P.B.; Patel, P.K.; Panchal, C.J.

    2005-01-01

    Indium sesquitelluride (In 2 Te 3 ) compound was synthesized by mixing and melting the pure individual elements in stoichiometric proportions. The synthesized compound was utilized for the deposition of In 2 Te 3 thin films on glass and freshly cleaved NaCl substrates using flash evaporation technique. The structure of In 2 Te 3 thin films has been studied on the glass substrates by X-ray diffraction technique and on the cleavage faces of NaCl by electron diffraction technique. It was observed that the deposition from an ordered α-phase compound results in polycrystalline films on glass substrate at 473 K which are predominant α-phase and random β-phase compounds resulting in single crystal films on NaCl substrate at 523 K. Effect of source and substrate temperature on the composition of In 2 Te 3 was also studied

  12. Optical and electrical properties of TiOPc doped Alq{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ramar, M.; Suman, C. K., E-mail: sumanck@nplindia.org; Tyagi, Priyanka; Srivastava, R. [CSIR-Network of Institutes for Solar Energy CSIR - National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi -110012 (India)

    2015-06-24

    The Titanyl phthalocyanine (TiOPc) was doped in Tris (8-hydroxyquinolinato) aluminum (Alq3) with different concentration. The thin film of optimized doping concentration was studied extensively for optical and electrical properties. The optical properties, studied using ellipsometry, absorption and photoluminescence. The absorption peak of Alq{sub 3} and TiOPc was observed at 387 nm and 707 nm and the photo-luminescence intensity (PL) peak of doped thin film was observed at 517 nm. The DC and AC electrical properties of the thin film were studied by current density-voltage (J-V) characteristics and impedance over a frequency range of 100 Hz - 1 MHz. The electron mobility calculated from trap-free space-charge limited region (SCLC) is 0.17×10{sup −5} cm{sup 2}/Vs. The Cole-Cole plots shows that the TiOPc doped Alq{sub 3} thin film can be represented by a single parallel resistance R{sub P} and capacitance C{sub P} network with a series resistance R{sub S} (10 Ω). The value of R{sub P} and C{sub P} at zero bias was 1587 Ω and 2.568 nF respectively. The resistance R{sub P} decreases with applied bias whereas the capacitance C{sub P} remains almost constant.

  13. Dynamic Displacement Disorder of Cubic BaTiO3

    Science.gov (United States)

    Paściak, M.; Welberry, T. R.; Kulda, J.; Leoni, S.; Hlinka, J.

    2018-04-01

    The three-dimensional distribution of the x-ray diffuse scattering intensity of BaTiO3 has been recorded in a synchrotron experiment and simultaneously computed using molecular dynamics simulations of a shell model. Together, these have allowed the details of the disorder in paraelectric BaTiO3 to be clarified. The narrow sheets of diffuse scattering, related to the famous anisotropic longitudinal correlations of Ti ions, are shown to be caused by the overdamped anharmonic soft phonon branch. This finding demonstrates that the occurrence of narrow sheets of diffuse scattering agrees with a displacive picture of the cubic phase of this textbook ferroelectric material. The presented methodology allows one to go beyond the harmonic approximation in the analysis of phonons and phonon-related scattering.

  14. Structural and Optical Properties of Ultra-high Pure Hot Water Processed Ga2O3 Thin Film

    Directory of Open Access Journals (Sweden)

    Subramani SHANMUGAN

    2016-05-01

    Full Text Available Thin film based gas sensor is an advanced application of thin film especially Ga2O3 (GO thin film gas sensor is useful for high temperature gas sensor. The effect of moisture or environment on thin film properties has more influence on gas sensing properties. Radio Frequency sputtered Ga2O3 thin film was synthesized and processed in ultra-high pure hot water at 95 °C for different time durations. The structural properties were verified by the Xray Diffraction technique and the observed spectra revealed the formation of hydroxyl compound of Gallium (Gallium Oxide Dueterate – GOD on the surface of the thin film and evidenced for structural defects as an effect of moisture. Decreased crystallite size and increased dislocation density was showed the crystal defects of prepared film. From the Ultra Violet – Visible spectra, decreased optical transmittance was noticed for various processing time. The formation of needle like GOD was confirmed using Field Emission Secondary Electron Microscope (FESEM images.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.7186

  15. Liquid flow deposited spinel (Ni,Mn){sub 3}O{sub 4} thin films for microbolometer applications

    Energy Technology Data Exchange (ETDEWEB)

    Le, Duc Thang, E-mail: ducthang36@skku.edu [Intelligent Electronic Component Team, Electronic Materials Convergence Division, Korea Institute of Ceramic Engineering and Technology, Seoul 153-801 (Korea, Republic of); School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Jeon, Chang Jun; Lee, Kui Woong; Jeong, Young Hun; Yun, Ji Sun [Intelligent Electronic Component Team, Electronic Materials Convergence Division, Korea Institute of Ceramic Engineering and Technology, Seoul 153-801 (Korea, Republic of); Yoon, Dae Ho, E-mail: dhyoon@skku.edu [School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Cho, Jeong Ho, E-mail: goedc@kicet.re.kr [Intelligent Electronic Component Team, Electronic Materials Convergence Division, Korea Institute of Ceramic Engineering and Technology, Seoul 153-801 (Korea, Republic of)

    2015-03-01

    Highlights: • Highly quality (Ni,Mn){sub 3}O{sub 4} thin films were grown using liquid flow deposited (LFD) technique. • It is possible to deposit multi–component manganite–oxide thin films by LFD at low temperatures. • Nickel–manganite films showed a good negative temperature coefficient (NTC) characteristic. • Liquid flow deposited (Ni,Mn){sub 3}O{sub 4} thin films are very potential for microbolometer applications. - Abstract: A liquid flow deposition (LFD) technique was initially used for the fabrication of single-component Mn{sub 3}O{sub 4} thin films onto Si wafer substrates at a range of substrate temperatures of 30–80 °C, with the introduction of an oxidizing reagent (H{sub 2}O{sub 2}). As a result, solid thin films were well formed from an aqueous solution. An X-ray diffraction (XRD) analysis showed typical characteristics of hausmannite Mn{sub 3}O{sub 4} with a spinel tetragonal phase. Field-emission scanning electron microscopy (FE-SEM) observations revealed nano-sized grains arranged uniformly on a dense and smooth surface for all of the as-deposited films. On the other hand, the LFD method was then extended to prepare two-component nickel–manganite films according to the binary chemical composition of Ni{sub x}Mn{sub 3−x}O{sub 4} with x = 0.02–0.2. The as-grown nickel–manganite films showed a surface with a good quality with a spherical bead-like architecture when x ≤ 0.10, while a conversion from spherical grains into highly porous nanowalls in the microstructure was noted in films when x ≥ 0.12. These results signify that it is possible to fabricate various multi-component manganite-oxide thin films at a low temperature. In addition, the dependences of the room-temperature electrical resistivity (ρ) and the temperature coefficient of resistance (TCR) on the Ni substitution level (x) were investigated on films annealed at 400 °C.

  16. Magneto-optical properties of BiFeO{sub 3} thin films using surface plasmon resonance technique

    Energy Technology Data Exchange (ETDEWEB)

    Paliwal, Ayushi; Sharma, Anjali [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Tomar, Monika [Physics Department, Miranda House, University of Delhi, Delhi 110007 (India); Gupta, Vinay, E-mail: drguptavinay@gmail.com [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2014-09-01

    Indigeneously assembled surface plasmon resonance (SPR) set up has been exploited to study the magnetic field dependent optical properties of BiFeO{sub 3} thin films. BiFeO{sub 3} thin films have been deposited onto gold (Au) coated glass prism by using pulsed laser deposition technique. The surface plasmon modes in prism/Au/BiFeO{sub 3}/air structure have been excited in Kretschmann configuration at the interface of Au/BiFeO{sub 3} thin films. The SPR reflectance curves obtained for prism/Au/BiFeO{sub 3}/air structure were utilized to investigate the optical properties of BiFeO{sub 3} thin films at optical frequency (λ=633 nm) as a function of applied magnetic field. SPR curves shows a continuous shift towards lower angles with increasing applied magnetic field, which indicate the promising application of ferromagnetic BiFeO{sub 3} film as a magnetic field sensor. Complex dielectric constant of deposited BiFeO{sub 3} film was determined by fitting the experimental SPR data with Fresnel's equations. The variation of complex dielectric constant and refractive index of BiFeO{sub 3} film was studied with increase in magnetic field, and the sensitivity of magnetic field sensor was found to be about 0.52 RIU/T.

  17. Pyrolyzed thin film carbon

    Science.gov (United States)

    Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

    2010-01-01

    A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

  18. Optimization of excess Bi doping to enhance ferroic orders of spin casted BiFeO3 thin film

    International Nuclear Information System (INIS)

    Gupta, Surbhi; Gupta, Vinay; Tomar, Monika; James, A. R.; Pal, Madhuparna; Guo, Ruyan; Bhalla, Amar

    2014-01-01

    Multiferroic Bismuth Ferrite (BiFeO 3 ) thin films with varying excess bismuth (Bi) concentration were grown by chemical solution deposition technique. Room temperature multiferroic properties (ferromagnetism, ferroelectricity, and piezoelectricity) of the deposited BiFeO 3 thin films have been studied. High resolution X-ray diffraction and Raman spectroscopy studies reveal that the dominant phases formed in the prepared samples change continuously from a mixture of BiFeO 3 and Fe 2 O 3 to pure BiFeO 3 phase and, subsequently, to a mixture of BiFeO 3 and Bi 2 O 3 with increase in the concentration of excess Bi from 0% to 15%. BiFeO 3 thin films having low content (0% and 2%) of excess Bi showed the traces of ferromagnetic phase (γ-Fe 2 O 3 ). Deterioration in ferroic properties of BiFeO 3 thin films is also observed when prepared with higher content (15%) of excess Bi. Single-phased BiFeO 3 thin film prepared with 5% excess Bi concentration exhibited the soft ferromagnetic hysteresis loops and ferroelectric characteristics with remnant polarization 4.2 μC/cm 2 and saturation magnetization 11.66 emu/g. The switching of fine spontaneous domains with applied dc bias has been observed using piezoresponse force microscopy in BiFeO 3 thin films having 5% excess Bi. The results are important to identify optimum excess Bi concentration needed for the formation of single phase BiFeO 3 thin films exhibiting the improved multiferroic properties.

  19. Syntheses of nanocrystalline BaTiO3 and their optical properties

    Science.gov (United States)

    Yu, J.; Chu, J.; Zhang, M.

    Stoichiometric and titanium-excess nanocrystalline barium titanates were synthesized using a hydrothermal process at various hydrothermal temperatures and with further heat treatment at 500 °C and 900 °C. Owing to the different process conditions, the excess titanium exists in different states and configurations within the nanocrystalline BaTiO3 matrix; this was demonstrated by X-ray diffraction, Raman scattering, and photoluminescence. In these nanocrystalline BaTiO3, the 590, 571, 543 and 694 nm light emission bands were observed; mechanisms leading to such emissions were also discussed.

  20. Photovoltaic effect in transition metal modified polycrystalline BiFeO3 thin films

    International Nuclear Information System (INIS)

    Puli, Venkata Sreenivas; Chrisey, Douglas B; Pradhan, Dhiren Kumar; Katiyar, Rajesh Kumar; Misra, Pankaj; Scott, J F; Katiyar, Ram S; Coondoo, Indrani; Panwar, Neeraj

    2014-01-01

    We report photovoltaic (PV) effect in multiferroic Bi 0.9 Sm 0.1 Fe 0.95 Co 0.05 O 3 (BSFCO) thin films. Transition metal modified polycrystalline BiFeO 3 (BFO) thin films have been deposited on Pt/TiO 2 /SiO 2 /Si substrate successfully through pulsed laser deposition (PLD). PV response is observed under illumination both in sandwich and lateral electrode configurations. The open-circuit voltage (V oc ) and the short-circuit current density (J sc ) of the films in sandwich electrode configuration under illumination are measured to be 0.9 V and −0.051 µA cm −2 . Additionally, we report piezoresponse for BSFCO films, which confirms ferroelectric piezoelectric behaviour. (paper)

  1. Structure and optical properties of thin As{sub 2}S{sub 3}-In{sub 2}S{sub 3} films

    Energy Technology Data Exchange (ETDEWEB)

    Todorov, R; Pirov, J; Petkov, K [Institute of Optical Materials and Technologies ' Acad. J. Malinowski' , Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl.109, 1113 Sofia (Bulgaria); Tsankov, D, E-mail: rossen@clf.bas.bg [Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev St. bl.9, 1113 Sofia (Bulgaria)

    2011-08-03

    This paper deals with the optical properties of thin As{sub 2}S{sub 3}-In{sub 2}S{sub 3} films. The thin layers were deposited by thermal co-evaporation of As{sub 2}S{sub 3} and In{sub 2}S{sub 3}. The composition of the coatings was controlled by x-ray microanalysis; it was found to be close to the expected one. The refractive index n and optical band gap E{sub g}{sup opt} were calculated from the transmittance and reflectance spectra. The results showed that the refractive index of thin As-S films is not affected by the addition of 1 at% indium and it increases from 2.46 to 2.58 for thin film with 13 at% In. A decrease in the changes in the refractive index, {Delta}n, after exposure to light or annealing with addition of indium in arsenic sulfide is observed. To explain the influence of the indium on the photoinduced changes in the optical properties of thin As-S-In films, the glass structure was investigated by infrared spectroscopy. The calculated values of the optical constants were compared with those obtained from ellipsometric measurements.

  2. Electrochemical synthesis of photoactive In/sub 2/Se/sub 3/ thin films

    Energy Technology Data Exchange (ETDEWEB)

    Herrero, J; Ortega, J

    1987-12-01

    In/sub 2/Se/sub 3/ thin films were grown by alternate electrodeposition of selenium and indium from separate baths onto titanium substrates with subsequent thermal annealing. The influence of annealing temperature on the properties of the obtained films was examined. The results of X-ray diffraction patterns led to the conclusion that films were ..beta..-phase when the temperature ranged between 300 and 500/sup 0/C. At 600/sup 0/C the thin film loses Se and the ratio Se/In decreases. Only photoanodic response, n-type thin films, was observed when the samples were tested in a photoelectrochemical cell with a sulfite/sulfate redox couple. Values of the photocurrent on the spectra response were increased when the annealing temperature was also increased, showing the best photocurrent values at 500/sup 0/C, and the films that were annealed at 600/sup 0/C showed no photoactivity. Spectral responses after chemical etching of the samples showed a significant increase of the photocurrent. Application of Gaertner-Butler's model to the interface semiconductor-electrolyte makes it possible to obtain the semiconductor energy gap, on samples heated at 500/sup 0/C, corresponding to a direct allowed band transition.

  3. Dependence on film thickness of grain boundary low-field magnetoresistance in thin films of La0.7Ca0.3MnO3

    International Nuclear Information System (INIS)

    Todd, N. K.; Mathur, N. D.; Blamire, M. G.

    2001-01-01

    The magnetoresistance of grain boundaries in the perovskite manganites is being studied, both in polycrystalline materials, and thin films grown on bicrystal substrates, because of interest in low-field applications. In this article we show that epitaxial films grown on SrTiO 3 bicrystal substrates of 45 degree misorientation show magnetoresistance behavior which is strongly dependent on the thickness of the film. Thin films, e.g., 40 nm, can show a large low-field magnetoresistance at low temperatures, with very sharp switching between distinct high and low resistance states for fields applied in plane and parallel to the boundary. Thicker films show a more complex behavior of resistance as a function of field, and the dependence on the angle between the applied field and the grain boundary is altered. These changes in magnetoresistance behavior are linked to the variation in morphology of the films. Thin films are coherently strained, due to the mismatch with the substrate, and very smooth. Thicker films relax, with the formation of defects, and hence different micromagnetic behavior. [copyright] 2001 American Institute of Physics

  4. thin films

    Indian Academy of Sciences (India)

    microscopy (SEM) studies, respectively. The Fourier transform ... Thin films; chemical synthesis; hydrous tin oxide; FTIR; electrical properties. 1. Introduction ... dehydrogenation of organic compounds (Hattori et al 1987). .... SEM images of (a) bare stainless steel and (b) SnO2:H2O thin film on stainless steel substrate at a ...

  5. CVD growth and characterization of 3C-SiC thin films

    Indian Academy of Sciences (India)

    Unknown

    Cubic silicon carbide (3C-SiC) thin films were grown on (100) and (111) Si substrates by CVD technique using ... of grown films were studied using optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and X-ray ... the oxide mask gets damaged (Edgar et al 1998). There- fore, lower ...

  6. Investigation of growth, structural and electronic properties of V2O3 thin films on selected substrates

    International Nuclear Information System (INIS)

    Nateprov, Alexei

    2006-08-01

    The present work is devoted to the experimental study of the MI transition in V 2 O 3 thin films, grown on different substrates. The main goal of the work was to develop a technology of growth of V 2 O 3 thin films on substrates with different electrical and structural properties (diamond and LiNbO 3 ), designed for specific applications. The structural and electrical properties of the obtained films were characterized in detail with a special focus on their potential applications. The MIT of V 2 O 3 was investigated by SAW using first directly deposited V 2 O 3 thin film onto a LiNbO 3 substrate. (orig.)

  7. Spray pyrolyzed Cu2SnS3 thin films for photovoltaic application

    Science.gov (United States)

    Patel, Biren; Waldiya, Manmohansingh; Pati, Ranjan K.; Mukhopadhyay, Indrajit; Ray, Abhijit

    2018-05-01

    We report the fabrication of Cu2SnS3 (CTS) thin films by a non-vacuum and low cost spray pyrolysis technique. Annealing of the as-deposited film in the sulphur atmosphere produces highly stoichiometric, granular and crystalline CTS phase. The CTS thin films shows direct optical band gap of 1.58 eV with high absorption coefficient of 105 cm-1. Hall measurement shows the carrier concentration of the order of 1021 cm-3 and a favourable resistivity of 10-3 Ω cm. A solar cell architecture of Glass/FTO/CTS/CdS/Al:ZnO/Al was fabricated and its current-voltage characteristic shows an open circuit voltage, short circuit current density and fill-factor of 12.6 mV, 20.2 µA/cm2 and 26% respectively. A further improvement in the solar cell parameters is underway.

  8. Solid phase epitaxial growth of high mobility La:BaSnO_3 thin films co-doped with interstitial hydrogen

    International Nuclear Information System (INIS)

    Niedermeier, Christian A.; Rhode, Sneha; Fearn, Sarah; Moram, Michelle A.; Ide, Keisuke; Hiramatsu, Hidenori; Hosono, Hideo; Kamiya, Toshio

    2016-01-01

    This work presents the solid phase epitaxial growth of high mobility La:BaSnO_3 thin films on SrTiO_3 single crystal substrates by crystallization through thermal annealing of nanocrystalline thin films prepared by pulsed laser deposition at room temperature. The La:BaSnO_3 thin films show high epitaxial quality and Hall mobilities up to 26 ± 1 cm"2/Vs. Secondary ion mass spectroscopy is used to determine the La concentration profile in the La:BaSnO_3 thin films, and a 9%–16% La doping activation efficiency is obtained. An investigation of H doping to BaSnO_3 thin films is presented employing H plasma treatment at room temperature. Carrier concentrations in previously insulating BaSnO_3 thin films were increased to 3 × 10"1"9" cm"−"3 and in La:BaSnO_3 thin films from 6 × 10"1"9" cm"−"3 to 1.5 × 10"2"0" cm"−"3, supporting a theoretical prediction that interstitial H serves as an excellent n-type dopant. An analysis of the free electron absorption by infrared spectroscopy yields a small (H,La):BaSnO_3 electron effective mass of 0.27 ± 0.05 m_0 and an optical mobility of 26 ± 7 cm"2/Vs. As compared to La:BaSnO_3 single crystals, the smaller electron mobility in epitaxial thin films grown on SrTiO_3 substrates is ascribed to threading dislocations as observed in high resolution transmission electron micrographs.

  9. Investigation of CaTiO3:Pr3+ thin films deposited by radiofrequency reactive magnetron sputtering for electroluminescence application

    International Nuclear Information System (INIS)

    Sarakha, L; Bousquet, A; Tomasella, E; Boutinaud, P; Mahiou, R

    2010-01-01

    In this report we successfully deposited thin films of CaTiO 3 :Pr 3+ by radiofrequency magnetron sputtering. The films were studied and we tried to understand the evolution of their optical and electrical properties. We noticed that the annealing temperature and the deposition pressures have an important influence on these properties. Thin films with good optical and electrical properties have been obtained. These films are transparent and are characterized by an intense red photoluminescence and a low fixed charge density. They are well dedicated for electroluminescence purposes.

  10. Effects of vacancies on atom displacement threshold energy calculations through Molecular Dynamics Methods in BaTiO3

    Science.gov (United States)

    Gonzalez Lazo, Eduardo; Cruz Inclán, Carlos M.; Rodríguez Rodríguez, Arturo; Guzmán Martínez, Fernando; Abreu Alfonso, Yamiel; Piñera Hernández, Ibrahin; Leyva Fabelo, Antonio

    2017-09-01

    A primary approach for evaluating the influence of point defects like vacancies on atom displacement threshold energies values Td in BaTiO3 is attempted. For this purpose Molecular Dynamics Methods, MD, were applied based on previous Td calculations on an ideal tetragonal crystalline structure. It is an important issue in achieving more realistic simulations of radiation damage effects in BaTiO3 ceramic materials. It also involves irradiated samples under severe radiation damage effects due to high fluency expositions. In addition to the above mentioned atom displacement events supported by a single primary knock-on atom, PKA, a new mechanism was introduced. It corresponds to the simultaneous excitation of two close primary knock-on atoms in BaTiO3, which might take place under a high flux irradiation. Therefore, two different BaTiO3 Td MD calculation trials were accomplished. Firstly, single PKA excitations in a defective BaTiO3 tetragonal crystalline structure, consisting in a 2×2×2 BaTiO3 perovskite like super cell, were considered. It contains vacancies on Ba and O atomic positions under the requirements of electrical charge balance. Alternatively, double PKA excitations in a perfect BaTiO3 tetragonal unit cell were also simulated. On this basis, the corresponding primary knock-on atom (PKA) defect formation probability functions were calculated at principal crystal directions, and compared with the previous one we calculated and reported at an ideal BaTiO3 tetrahedral crystal structure. As a general result, a diminution of Td values arises in present calculations in comparison with those calculated for single PKA excitation in an ideal BaTiO3 crystal structure.

  11. Ferroelectric properties of composites containing BaTiO3 nanoparticles of various sizes

    International Nuclear Information System (INIS)

    Adam, Jens; Lehnert, Tobias; Klein, Gabi; McMeeking, Robert M

    2014-01-01

    Size effects, including the occurrence of superparaelectric phases associated with small scale, are a significant research topic for ferroelectrics. Relevant phenomena have been explored in detail, e.g. for homogeneous, thin ferroelectric films, but the related effects associated with nanoparticles are usually only inferred from their structural properties. In contrast, this paper describes all the steps and concepts necessary for the direct characterization and quantitative assessment of the ferroelectric properties of as-synthesized and as-received nanoparticles. The method adopted uses electrical polarization measurements on polymer matrix composites containing ferroelectric nanoparticles. It is applied to ten different BaTiO 3 particle types covering a size range from 10 nm to 0.8 μm. The influence of variations of particle characteristics such as tetragonality and dielectric constant is considered based on measurements of these properties. For composites containing different particle types a clearly differing polarization behaviour is found. For decreasing particle size, increasing electric field is required to achieve a given level of polarization. The size dependence of a measure related to the coercive field revealed by this work is qualitatively in line with the state of the knowledge for ferroelectrics having small dimensions. For the first time, such results and size effects are described based on data from experiments on collections of actual nanoparticles. (paper)

  12. Ferroelectric properties of composites containing BaTiO 3 nanoparticles of various sizes

    Science.gov (United States)

    Adam, Jens; Lehnert, Tobias; Klein, Gabi; McMeeking, Robert M.

    2014-01-01

    Size effects, including the occurrence of superparaelectric phases associated with small scale, are a significant research topic for ferroelectrics. Relevant phenomena have been explored in detail, e.g. for homogeneous, thin ferroelectric films, but the related effects associated with nanoparticles are usually only inferred from their structural properties. In contrast, this paper describes all the steps and concepts necessary for the direct characterization and quantitative assessment of the ferroelectric properties of as-synthesized and as-received nanoparticles. The method adopted uses electrical polarization measurements on polymer matrix composites containing ferroelectric nanoparticles. It is applied to ten different BaTiO3 particle types covering a size range from 10 nm to 0.8 μm. The influence of variations of particle characteristics such as tetragonality and dielectric constant is considered based on measurements of these properties. For composites containing different particle types a clearly differing polarization behaviour is found. For decreasing particle size, increasing electric field is required to achieve a given level of polarization. The size dependence of a measure related to the coercive field revealed by this work is qualitatively in line with the state of the knowledge for ferroelectrics having small dimensions. For the first time, such results and size effects are described based on data from experiments on collections of actual nanoparticles.

  13. Study of radiation damage in BaTiO3, using Molecular-dynamics simulations

    International Nuclear Information System (INIS)

    Gonzalez, E.; Abreu, Y.; Cruz, C. M.; Pinnera, I.; Leyva, A.

    2015-01-01

    Molecular-dynamics (MD) simulations were used to calculate atomic displacement probability curves along main crystallographic directions in BaTiO 3 perovskite. A primary knock-on atom (PKA) with a energy range between 10 to 300 eV in principal crystallographic directions at 300 K was introduced. For each sublattice, the simulation was repeated from different initial conditions to estimate the variation in the defect formation process. The formation of Frenkel pairs vary considerably with crystallographic direction and sublattice. Major quantity oxygen defects were found for all the simulated crystallographic directions. Threshold displacement energies are calculated for each atomic specie in the BaTiO 3 material. Also simulations with SRIM code, modeling + Mn implantation in a BaTiO 3 target, at 250 keV were made. (Author)

  14. Characterization and dielectric properties of BaTiO3 prepared from Ba(NO3)2-TiO2 mixture

    International Nuclear Information System (INIS)

    Othman, K.I.; Hassan, A.A.; Ali, M.E.; Abdelal, O.A.; Salah El Dien, F.E.; El-Raghy, S.M.; Abdel-Karim, R.

    2012-01-01

    BaTiO 3 powder was prepared through a solid-state reaction between the Ba(NO 3 ) 2 and TiO 2 . The thermal analysis and XRD techniques were used to study its formation. A single phase BaTiO 3 was formed after calcination at 600 degree C for 6 hrs. The dielectric properties of the sintered BaTiO 3 were determined in the temperature range from room temperature to 20 degree C at a frequency ranging from 500 Hz to 100 khz. The relative permittivity and the dielectric loss of the sintered pellets at 1 khz, measured at room temperature,were 1805 and 0.419 respectively.

  15. Influence of Impurities on the Luminescence of Er3+ Doped BaTiO3 Nanophosphors

    Directory of Open Access Journals (Sweden)

    G. D. Webler

    2014-01-01

    Full Text Available The influence of the presence of barium carbonate (BaCO3 phase on the luminescence properties of barium titanate nanocrystals (BaTiO3 powders was investigated. Structural and optical characterizations of erbium (Er3+ doped BaTiO3 synthesized by the sol-emulsion-gel were performed. Using Fourier transform infrared spectroscopy and X-ray powder diffraction, we identified the presence of impurities related to BaCO3 and quantified its fraction. It was observed that the presence of BaCO3 phase, even at low levels, depletes significantly the infrared-to-visible upconverted luminescence efficiency of the produced nanopowders.

  16. Photoinduced hydrophobic surface of graphene oxide thin films

    International Nuclear Information System (INIS)

    Zhang Xiaoyan; Song Peng; Cui Xiaoli

    2012-01-01

    Graphene oxide (GO) thin films were deposited on transparent conducting oxide substrates and glass slides by spin coating method at room temperature. The wettability of GO thin films before and after ultraviolet (UV) irradiation was characterized with water contact angles, which increased from 27.3° to 57.6° after 3 h of irradiation, indicating a photo-induced hydrophobic surface. The UV–vis absorption spectra, Raman spectroscopy, X-ray photoelectron spectroscopy, and conductivity measurements of GO films before and after UV irradiation were taken to study the mechanism of photoinduced hydrophobic surface of GO thin films. It is demonstrated that the photoinduced hydrophobic surface is ascribed to the elimination of oxygen-containing functional groups on GO molecules. This work provides a simple strategy to control the wettability properties of GO thin films by UV irradiation. - Highlights: ► Photoinduced hydrophobic surface of graphene oxide thin films has been demonstrated. ► Elimination of oxygen-containing functional groups in graphene oxide achieved by UV irradiation. ► We provide novel strategy to control surface wettability of GO thin films by UV irradiation.

  17. Epitaxial Pb(Mg1/3Nb2/3)O3 thin films synthesized by metal-organic chemical vapor deposition

    International Nuclear Information System (INIS)

    Bai, G. R.; Streiffer, S. K.; Baumann, P. K.; Auciello, O.; Ghosh, K.; Stemmer, S.; Munkholm, A.; Thompson, Carol; Rao, R. A.; Eom, C. B.

    2000-01-01

    Metal-organic chemical vapor deposition was used to prepare Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) thin films on (001) SrTiO 3 and SrRuO 3 /SrTiO 3 substrates, using solid Mg β-diketonate as the Mg precursor. Parameters including the precursor ratio in the vapor phase, growth temperature, growth rate, and reaction pressure in the reactor chamber were varied in order to determine suitable growth conditions for producing phase-pure, epitaxial PMN films. A cube-on-cube orientation relationship between the thin film and the SrTiO 3 substrate was found, with a (001) rocking curve width of 0.1 degree sign , and in-plane rocking-curve width of 0.8 degree sign . The root-mean-square surface roughness of a 200-nm-thick film on SrTiO 3 was 2 to 3 nm as measured by scanning probe microscopy. The zero-bias dielectric constant and loss measured at room temperature and 10 kHz for a 200-nm-thick film on SrRuO 3 /SrTiO 3 were approximately 1100 and 2%, respectively. The remnant polarization for this film was 16 μC/cm 2 . (c) 2000 American Institute of Physics

  18. Structural and optical properties of annealed and illuminated (Ag3AsS3)0.6(As2S3)0.4 thin films

    Science.gov (United States)

    Studenyak, I. P.; Neimet, Yu. Yu.; Rati, Y. Y.; Stanko, D.; Kranjčec, M.; Kökényesi, S.; Daróci, L.; Bohdan, R.

    2014-11-01

    (Ag3AsS3)0.6(As2S3)0.4 thin films were deposited upon a quartz substrate by rapid thermal evaporation. Structural studies of the as-deposited, annealed and illuminated films were performed using XRD, scanning electron and atomic force microscopies. Surfaces of all the films were found to be covered with Ag-rich crystalline micrometer sized cones. Thermal annealing leads to mechanical deformation of part of the cones and their detachment from the base film surface while the laser illumination leads to the new formations appearance on the surface of thin films. The spectroscopic studies of optical transmission spectra for as-deposited, annealed and illuminated thin films were carried out. The optical absorption spectra in the region of its exponential behaviour were analysed, the dispersion dependences of refractive index as well as their variation after annealing and illumination were investigated.

  19. Photovoltaics: tests of thin-film technologies. 6 thin-film technologies in 3 different BIPV modes compared in a real outdoor performance test; PV-ThinFilmTest. 6 thin-film technologies in 3 different BIPV modes compared in a real outdoor performance test

    Energy Technology Data Exchange (ETDEWEB)

    Frei, R.; Meier, Ch.

    2005-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of a comparison made between six types of thin-film, building-integrated photovoltaic (BIPV) technologies used in three different modes of building-integration. More than 450 thin-film modules including amorphous silicon and CIS technologies were monitored. Each type of module was installed in three different modes: inclined (20{sup o}), flat with free back air flow, and flat with thermal back insulation. The performance of these commercially available thin-film BIPV systems was monitored using an extensive monitoring program. Additionally, three mono-crystalline PV arrays allowed direct comparison of the technologies. The results of the monitoring work are presented and further work to be done is discussed, including the monitoring of possible long-term degradation.

  20. Etude de capacités en couches minces à base d'oxydes métalliques à très forte constante diélectrique, BaTiO3, SrTiO3 et SrTiO3/BaTiO3 déposées par pulvérisation par faisceau d'ions

    OpenAIRE

    Guillan , Julie

    2005-01-01

    In a view of miniaturization in microelectronics and more particularly in the sector of mobile phone, perovskites materials with very high permittivity are interesting candidates to replace dielectrics currently used in the development of Metal/Insulator/Metal (MIM) capacitor. This work is devoted to the development and the characterization of thin layers of strontium titanate (SrTiO3) and barium titanate (BaTiO3) deposited by Ion Beam Sputtering (IBS) in capacitive structure Pt/high-k/Pt.An ...

  1. Optical, structural and electrochromic behavior studies on nanocomposite thin film of aniline, o-toluidine and WO3

    Science.gov (United States)

    Najafi-Ashtiani, Hamed; Bahari, Ali

    2016-08-01

    In the field of materials for electrochromic (EC) applications much attention was paid to the derivatives of aniline. We report on the optical, structural and electrochromic properties of electrochromic thin film based on composite of WO3 nanoparticles and copolymer of aniline and o-toluidine prepared by electrochemical polymerization method on fluorine doped tin oxide (FTO) coated glass. The thin film was studied by X-ray diffraction (XRD) and Fourier transforms infrared (FTIR) spectroscopy. The morphology of prepared thin film was characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and the thermal gravimetric analysis (TGA) as well. The optical spectra of nanocomposite thin film were characterized in the 200-900 nm wavelength range and EC properties of nanocomposite thin film were studied by cyclic voltammetry (CV). The calculation of optical band gaps of thin film exhibited that the thin film has directly allowed transition with the values of 2.63 eV on first region and 3.80 eV on second region. Dispersion parameters were calculated based on the single oscillator model. Finally, important parameters such as dispersion energy, oscillator energy and lattice dielectric constant were determined and compared with the data from other researchers. The nonlinear optical properties such as nonlinear optical susceptibility, nonlinear absorption coefficient and nonlinear refractive index were extracted. The obtained results of nanocomposite thin film can be useful for the optoelectronic applications.

  2. Electrical transport in (103) YBa2Cu3O7-x thin films

    International Nuclear Information System (INIS)

    Divin, Yu.Ya.; Poppe, U.; Faley, M.I.; Soltner, H.; Seo, J.W.; Kabius, B.; Urban, K.

    1993-01-01

    We have studied the electrical and structural properties of (103) YBa 2 Cu 3 O 7-x thin films to estimate the applicability of these films as base electrodes of planar-type Josephson junctions. (orig.)

  3. Structural characterization of PbTi03, Sm0.6Nd0.4NiO3 and NdMnO3 multifunctional Perovskite thin films

    Directory of Open Access Journals (Sweden)

    Rapenne L.

    2012-06-01

    Full Text Available Different multifunctional (PbTiO3, Sm0.6Nd0.4NiO3, NdMnO3 thin films were grown by metalorganic chemical vapor deposition (MOCVD technique on SrTiO3 and LaAlO3 substrates. TEM and X-ray diffraction measurements reveal that almost single crystalline thin films can be epitaxially grown on the top of substrates. The relationship between the crystallographic orientation of the films and those of the substrates were determined by reciprocal space mapping and TEM analyses. PbTi03 thin films appear to be under tensile or compressive strain according to the different mismatch of their cell parameter with those of the substrate. Relaxation mechanism as a function of the film thickness arises from coexistence of different type of domains and size and strain effect are analyzed. SmNiO3 thin films present diffuse scattering strikes and are less well organized when compared to PbTi03 thin films. Different domains are observed as well as an additional parasitic phase close to NiO. Its regular distribution can be associated to reduced transport properties. Preliminary observations on NdMnO3 thin films show that an amorphous phase is obtained during MOCVD that can be transformed in a single crystalline film by annealing. The films are under tensile or compressive strain according to the different mismatch of their cell parameter with those of the substrate. Magnetic properties are investigated.

  4. Thermochemical hydrogen generation of indium oxide thin films

    Directory of Open Access Journals (Sweden)

    Taekyung Lim

    2017-03-01

    Full Text Available Development of alternative energy resources is an urgent requirement to alleviate current energy constraints. As such, hydrogen gas is gaining attention as a future alternative energy source to address existing issues related to limited energy resources and air pollution. In this study, hydrogen generation by a thermochemical water-splitting process using two types of In2O3 thin films was investigated. The two In2O3 thin films prepared by chemical vapor deposition (CVD and sputtering deposition systems contained different numbers of oxygen vacancies, which were directly related to hydrogen generation. The as-grown In2O3 thin film prepared by CVD generated a large amount of hydrogen because of its abundant oxygen vacancies, while that prepared by sputtering had few oxygen vacancies, resulting in low hydrogen generation. Increasing the temperature of the In2O3 thin film in the reaction chamber caused an increase in hydrogen generation. The oxygen-vacancy-rich In2O3 thin film is expected to provide a highly effective production of hydrogen as a sustainable and efficient energy source.

  5. Multiferroicity in oxide thin films and heterostructures

    International Nuclear Information System (INIS)

    Glavic, Artur

    2012-01-01

    In this work a variety of different systems of transition metal oxides ABO 3 (perovskite materials, where B stands for a transition metal and A for a rare earth element) were produced as thin films and heterostructures and analyzed for the structural, magnetic and ferroelectric properties. For the epitaxial film preparation mostly pulse laser deposition (PLD) was applied. For one series high pressure oxide sputter deposition was used as well. The bulk multiferroics TbMnO 3 and DyMnO 3 , which develop their electric polarization due to a cycloidal magnetic order, have been prepared as single layers with thicknesses between 2 and 200 nm on YAlO 3 substrates using PLD and sputter deposition. The structural characterization of the surfaces and crystal structure where performed using X-ray reflectometry and diffraction, respectively. These yielded low surface roughness and good epitaxial growth. The magnetic behavior was macroscopically measured with SQUID magnetometry and microscopically with polarized neutron diffraction and resonant magnetic X-ray scattering. While all investigated samples showed antiferromagnetic order, comparable with the collinear magnetic phase of their bulk materials, only the sputter deposited samples exhibited the multiferroic low temperature cycloidal order. The investigation of the optical second harmonic generation in a TbMnO 3 sample could proof the presence of a ferroelectric order in the low temperature phase. The respective transition temperatures of the thin films have been very similar to those of the bulk materials. In contrast an increase in the rare earth ordering temperature has been observed, which reduces the Mn order slightly, an effect not known from bulk TbMnO 3 crystals. The coupling of the antiferromagnetic order in TbMnO 3 to ferromagnetic layers of LaCoO 3 was investigated in super-lattices containing 20 bilayers produced with PLD on the same substrates. The SQUID magnetometry yielded a strong influence of the

  6. ESR and X-ray diffraction studies on thin films of poly-3-hexylthiophene: Molecular orientation and magnetic interactions

    International Nuclear Information System (INIS)

    Sugiyama, Keisuke; Kojima, Takashi; Fukuda, Hisashi; Yashiro, Hisashi; Matsuura, Toshihiko; Shimoyama, Yuhei

    2008-01-01

    Poly-3-hexylthiophene (P3HT) thin films were investigated by X-ray diffraction (XRD) and electron spin resonance (ESR) to reveal the film structure and molecular organization. The XRD data showed a diffraction pattern with a plane separation between the planes containing thiophene rings of 16.0 A. Comparison between the XRD patterns of powder and thin films of P3HT suggests that the main chains are folded on the substrate. Angular variation of the line position (g-value) of ESR spectra revealed that thiophene ring of P3HT orients along the substrate normal axis. The ESR linewidth varied by the angular rotation, indicating the one-dimensional spin-chain interactions in the P3HT thin films with a linear network of spin-chains. An organic thin-film transistor (OTFT) with P3HT film as a channel layer was then demonstrated. The P3HT films showed conducting characteristics with holes as carriers. The OTFTs indicated a field-effect mobility of 4.93 x 10 -3 cm 2 /Vs and an on/off ratio of 73 in the accumulation mode

  7. Gasochromic performance of WO3-nanorod thin films fabricated with an ArF excimer laser

    International Nuclear Information System (INIS)

    Yaacob, M. H.; Ou, J. Z.; Wlodarski, W.; Kim, C. S.; Lee, J. Y.; Kim, Y. H.; Oh, C. M.; Dhakal, K. P.; Kim, J. Y.; Kang, J. H.

    2012-01-01

    Thin films with tungsten trioxide (WO 3 ) nanorods were fabricated by using an ArF pulsed laser deposition system. Because the ArF excimer laser operates at a very short wavelength of 193 nm, short enough to expect strong absorption of the photons in the semiconductor oxide targets, and because the clusters incoming to the substrates have high momentum, we could build thin films with good surface morphology. Highly homogeneous arrays of nanorods with sizes mostly in the range of 30 - 40 nm were observed. The absorbance response towards hydrogen (H 2 ) gas was investigated for a WO 3 film coated with 25-A-thick palladium (Pd). The Pd/WO 3 -nanorod thin films exhibited excellent gasochromic response when measured in the visible-NIR range (400 - 1000 nm). As low as 0.06% H 2 concentration was clearly sensed. A significant reversible absorbance change and fast recovery ( 2 at different concentrations.

  8. Self-regulated growth of LaVO3 thin films by hybrid molecular beam epitaxy

    International Nuclear Information System (INIS)

    Zhang, Hai-Tian; Engel-Herbert, Roman; Dedon, Liv R.; Martin, Lane W.

    2015-01-01

    LaVO 3 thin films were grown on SrTiO 3 (001) by hybrid molecular beam epitaxy. A volatile metalorganic precursor, vanadium oxytriisopropoxide (VTIP), and elemental La were co-supplied in the presence of a molecular oxygen flux. By keeping the La flux fixed and varying the VTIP flux, stoichiometric LaVO 3 films were obtained for a range of cation flux ratios, indicating the presence of a self-regulated growth window. Films grown under stoichiometric conditions were found to have the largest lattice parameter, which decreased monotonically with increasing amounts of excess La or V. Energy dispersive X-ray spectroscopy and Rutherford backscattering measurements were carried out to confirm film compositions. Stoichiometric growth of complex vanadate thin films independent of cation flux ratios expands upon the previously reported self-regulated growth of perovskite titanates using hybrid molecular beam epitaxy, thus demonstrating the general applicability of this growth approach to other complex oxide materials, where a precise control over film stoichiometry is demanded by the application

  9. The film thickness dependent thermal stability of Al{sub 2}O{sub 3}:Ag thin films as high-temperature solar selective absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Xiao Xiudi; Xu Gang, E-mail: xiudixiao@163.com; Xiong Bin; Chen Deming; Miao Lei [Chinese Academy of Sciences, Key Laboratory of Renewable Energy and Gas Hydrates, Guangzhou Institute of Energy Conversion (China)

    2012-03-15

    The monolayer Al{sub 2}O{sub 3}:Ag thin films were prepared by magnetron sputtering. The microstructure and optical properties of thin film after annealing at 700 Degree-Sign C in air were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and spectrophotometer. It revealed that the particle shape, size, and distribution across the film were greatly changed before and after annealing. The surface plasmon resonance absorption and thermal stability of the film were found to be strongly dependent on the film thickness, which was believed to be associated with the evolution process of particle diffusion, agglomeration, and evaporation during annealing at high temperature. When the film thickness was smaller than 90 nm, the film SPR absorption can be attenuated until extinct with increasing annealing time due to the evaporation of Ag particles. While the film thickness was larger than 120 nm, the absorption can keep constant even after annealing for 64 h due to the agglomeration of Ag particles. On the base of film thickness results, the multilayer Al{sub 2}O{sub 3}:Ag solar selective thin films were prepared and the thermal stability test illustrated that the solar selectivity of multilayer films with absorbing layer thickness larger than 120 nm did not degrade after annealing at 500 Degree-Sign C for 70 h in air. It can be concluded that film thickness is an important factor to control the thermal stability of Al{sub 2}O{sub 3}:Ag thin films as high-temperature solar selective absorbers.

  10. Application-related properties of giant magnetostrictive thin films

    International Nuclear Information System (INIS)

    Lim, S.H.; Kim, H.J.; Na, S.M.; Suh, S.J.

    2002-01-01

    In an effort to facilitate the utilization of giant magnetostrictive thin films in microdevices, application-related properties of these thin films, which include induced anisotropy, residual stress and corrosion properties, are investigated. A large induced anisotropy with an energy of 6x10 4 J/m 3 is formed in field-sputtered amorphous Sm-Fe-B thin films, resulting in a large magnetostriction anisotropy. Two components of residual stress, intrinsic compressive stress and tensile stress due to the difference of the thermal expansion coefficients between the substrate and thin film, are identified. The variation of residual stress with fabrication parameter and annealing temperature, and its influence on mechanical bending and magnetic properties are examined. Better corrosion properties are observed in Sm-Fe thin films than in Tb-Fe. Corrosion properties of Tb-Fe thin films, however, are much improved with the introduction of nitrogen to the thin films without deteriorating magnetostrictive properties

  11. Highly textured fresnoite thin films synthesized in situ by pulsed laser deposition with CO2 laser direct heating

    International Nuclear Information System (INIS)

    Lorenz, Michael; Stölzel, Marko; Brachwitz, Kerstin; Hochmuth, Holger; Grundmann, Marius; De Pablos-Martin, Araceli; Patzig, Christian; Höche, Thomas

    2014-01-01

    Fresnoite Ba 2 TiSi 2 O 8 (BTS) thin films were grown and crystallized in situ using pulsed laser deposition (PLD) with CO 2 laser direct heating of the a-plane sapphire (1 1 0) substrates up to 1250 °C. Starting with 775 °C growth temperature, (0 0 1)- and (1 1 0)-textured BTS and BaTiO 3 phases, respectively, could be assigned in the films, and the typical fern-like BTS crystallization patterns appear. For higher process temperatures of 1100 to 1250 °C, atomically smooth, terraced surface of the films was found, accompanied by crystalline high-temperature phases of Ba–Ti–Si oxides. HAADF micrographs taken in both scanning transmission electron microscopy and energy-dispersive x-ray spectrometry mode show details of morphology and elemental distribution inside the films and at the interface. To balance the inherent Si deficiency of the BTS films, growth from glassy BTS × 2 SiO 2 and BTS × 2.5 SiO 2 targets was considered as well. The latter targets are ideal for PLD since the employed glasses possess 100% of the theoretical density and are homogeneous at the atomic scale. (paper)

  12. Operating method of amorphous thin film semiconductor element

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Koshiro; Ono, Masaharu; Hanabusa, Akira; Osawa, Michio; Arita, Takashi

    1988-05-31

    The existing technologies concerning amorphous thin film semiconductor elements are the technologies concerning the formation of either a thin film transistor or an amorphous Si solar cell on a substrate. In order to drive a thin film transistor for electronic equipment control by the output power of an amorphous Si solar cell, it has been obliged to drive the transistor weth an amorphous solar cell which was formed on a substrate different from that for the transistor. Accordingly, the space for the amorphous solar cell, which was formed on the different substrate, was additionally needed on the substrate for the thin film transistor. In order to solve the above problem, this invention proposes an operating method of an amorphous thin film semiconductor element that after forming an amorphous Si solar cell through lamination on the insulation coating film which covers the thin film transistor formed on the substrate, the thin film transistor is driven by the output power of this solar cell. The invention eliminates the above superfluous space and reduces the size of the amorphous thin film semiconductor element including the electric source. (3 figs)

  13. The effects of additive on microstructure and electrical properties of batio3 ceramics

    Directory of Open Access Journals (Sweden)

    Paunović Vesna V.

    2004-01-01

    Full Text Available In this paper comparative investigations of microstructure and dielectric properties of BaTiO3 ceramics doped with 1.0 wt% of Nb2O5, MnCO3 and CaZrO3 have been done. BaTiO3 samples were prepared using conventional method of solid state sintering at 13000C for two hours. Two distinguish micro structural regions can be observed in sample doped with Nb2O5. The first one, with a very small grained microstructure and the other one, with a rod like grains. In MnCO3 and CaZrO3 doped ceramics the uniform microstructure is formed with average grain size about 0.5- 2µm and 3-5µm respectively. The highest value of dielectric permittivity at room temperature and the greatest change of permittivity in function of temperature were observed in MnCO3/BaTiO3. In all investigated samples dielectric constant after initially large value at low frequency attains a constant value at f = 6kHz. A dissipation factor is independent of frequency greater than 10 kHz and, depending of systems, lies in the range from 0.035 to 0.25. At temperatures above Curie temperatures, the permittivity of all investigated samples follows a Curie- Weiss law. A slight shift of Curie temperature to the lower temperatures, in respect of Curie temperature for undoped BaTiO3, was observed in all investigated samples.

  14. Ceramic Composite Thin Films

    Science.gov (United States)

    Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor); Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor)

    2013-01-01

    A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

  15. Preparation of SrIrO{sub 3} thin films by using metal-organic aerosol deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Esser, Sebastian; Schneider, Melanie; Moshnyaga, Vasily; Gegenwart, Philipp [1. Physikalisches Institut, Georg-August-Universitaet Goettingen (Germany)

    2013-07-01

    The interplay between spin-orbit coupling and electronic correlations could lead to interesting novel states in iridium oxide materials. We focus on the perovskite phase of SrIrO{sub 3} because Moon et al. [1] showed by using optical spectroscopy and first-principles calculations that the last member of the Ruddlesden-Popper series Sr{sub n+1}Ir{sub n}O{sub 3n+1} (n = ∞) is close to the Mott transition. By using metal-organic aerosol deposition technique we have grown SrIrO{sub 3} thin films on (111)-oriented SrTiO{sub 3} substrates. The cubic symmetry of the SrTiO{sub 3} substrate ensured that the SrIrO{sub 3} thin film grew in the monoclinic perovskite phase. The X-ray diffraction results suggest that SrIrO{sub 3} thin films in perovskite structure were obtained and these show out of plane epitaxy with monoclinic (002){sub m}-orientation. The temperature dependence of the electrical resistivity of these SrIrO{sub 3} thin films were investigated and metallic behavior was observed down to 50 K.

  16. Preparation of Cu2Sn3S7 Thin-Film Using a Three-Step Bake-Sulfurization-Sintering Process and Film Characterization

    Directory of Open Access Journals (Sweden)

    Tai-Hsiang Lui

    2015-01-01

    Full Text Available Cu2Sn3S7 (CTS can be used as the light absorbing layer for thin-film solar cells due to its good optical properties. In this research, the powder, baking, sulfur, and sintering (PBSS process was used instead of vacuum sputtering or electrochemical preparation to form CTS. During sintering, Cu and Sn powders mixed in stoichiometric ratio were coated to form the thin-film precursor. It was sulfurized in a sulfur atmosphere to form CTS. The CTS film metallurgy mechanism was investigated. After sintering at 500°C, the thin film formed the Cu2Sn3S7 phase and no impurity phase, improving its energy band gap. The interface of CTS film is continuous and the formation of intermetallic compound layer can increase the carrier concentration and mobility. Therefore, PBSS process prepared CTS can potentially be used as a solar cell absorption layer.

  17. The structure and magnetic properties of β-(Ga0.96Mn0.04)2O3 thin film

    Science.gov (United States)

    Huang, Yuanqi; Chen, Zhengwei; Zhang, Xiao; Wang, Xiaolong; Zhi, Yusong; Wu, Zhenping; Tang, Weihua

    2018-05-01

    High quality epitaxial single phase (Ga0.96Mn0.04)2O3 and Ga2O3 thin films have been prepared on sapphire substrates by using laser molecular beam epitaxy (L-MBE). X-ray diffraction results indicate that the thin films have the monoclinic structure with a ≤ft( {\\bar 201} \\right) preferable orientation. Room temperature (RT) ferromagnetism appears and the magnetic properties of β-(Ga0.96Mn0.04)2O3 thin film are enhanced compared with our previous works. Experiments as well as the first principle method are used to explain the role of Mn dopant on the structure and magnetic properties of the thin films. The ferromagnetic properties are explained based on the concentration of transition element and the defects in the thin films. Project supported by the National Natural Science Foundation of China (Nos. 11404029, 51572033, 51172208) and the Fund of State Key Laboratory of Information Photonics and Optical Communications (BUPT).

  18. Effect of composition on properties of In2O3-Ga2O3 thin films

    Science.gov (United States)

    Demin, I. E.; Kozlov, A. G.

    2017-06-01

    The In2O3-Ga2O3 mixed oxide polycrystalline thin films with various ratios of components were obtained by pulsed laser deposition. The effect of films composition on surface morphology, electrophysical and gas sensing properties and energies of adsorption and desorption of combustible gases was studied. The films with50%In2O3-50%Ga2O3 composition showed maximum gas response (˜25 times) combined with minimum optimal working temperature (˜530 °C) as compared with the other films. The optical transmittance of the films in visible range was investigated. For 50%In2O3-50%Ga2O3 films, the transmittance is higher in comparison with the other films. The explanation of the dependency of films behaviors on their composition was presented.The In2O3-Ga2O3 films were assumed to have perspectives as gas sensing material for semiconducting gas sensors.

  19. Thin films prepared from tungstate glass matrix

    Energy Technology Data Exchange (ETDEWEB)

    Montanari, B.; Ribeiro, S.J.L.; Messaddeq, Y. [Departamento de Quimica Geral e Inorganica, Instituto de Quimica, Sao Paulo State University-UNESP, CP 355, CEP 14800-900, Araraquara, SP (Brazil); Li, M.S. [Instituto de Fisica, USP, CP 369, CEP 13560-970, Sao Carlos, SP (Brazil); Poirier, G. [Departamento de Ciencias Exatas, UNIFAL-MG, CEP 37130-000, Alfenas-MG (Brazil)], E-mail: gael@unifal-mg.edu.br

    2008-01-30

    Vitreous samples containing high concentrations of WO{sub 3} (above 40% M) have been used as a target to prepare thin films. Such films were deposited using the electron beam evaporation method onto soda-lime glass substrates. These films were characterized by X-ray diffraction (XRD), perfilometry, X-ray energy dispersion spectroscopy (EDS), M-Lines and UV-vis absorption spectroscopy. In this work, experimental parameters were established to obtain stable thin films showing a chemical composition close to the glass precursor composition and with a high concentration of WO{sub 3}. These amorphous thin films of about 4 {mu}m in thickness exhibit a deep blue coloration but they can be bleached by thermal treatment near the glass transition temperature. Such bleached films show several guided modes in the visible region and have a high refractive index. Controlled crystallization was realized and thus it was possible to obtain WO{sub 3} microcrystals in the amorphous phase.

  20. Resistive switching in polycrystalline YMnO3 thin films

    Directory of Open Access Journals (Sweden)

    A. Bogusz

    2014-10-01

    Full Text Available We report a unipolar, nonvolatile resistive switching in polycrystalline YMnO3 thin films grown by pulsed laser deposition and sandwiched between Au top and Ti/Pt bottom electrodes. The ratio of the resistance in the OFF and ON state is larger than 103. The observed phenomena can be attributed to the formation and rupture of conductive filaments within the multiferroic YMnO3 film. The generation of conductive paths under applied electric field is discussed in terms of the presence of grain boundaries and charged domain walls inherently formed in hexagonal YMnO3. Our findings suggest that engineering of the ferroelectric domains might be a promising route for designing and fabrication of novel resistive switching devices.

  1. Stabilization and enhanced energy gap by Mg doping in ɛ-phase Ga2O3 thin films

    Science.gov (United States)

    Bi, Xiaoyu; Wu, Zhenping; Huang, Yuanqi; Tang, Weihua

    2018-02-01

    Mg-doped Ga2O3 thin films with different doping concentrations were deposited on sapphire substrates using laser molecular beam epitaxy (L-MBE) technique. X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and ultraviolet-visible (UV-vis) absorption spectrum were used to characterize the crystal structure and optical properties of the as-grown films. Compared to pure Ga2O3 thin film, the Mg-doped thin films have transformed from the most stable β-phase into ɛ-phase. The absorption edge shifted to about 205 nm and the optical bandgap increased to ˜ 6 eV. These properties reveal that Mg-doped Ga2O3 films may have potential applications in the field of deep ultraviolet optoelectronic devices, such as deep ultraviolet photodetectors, short wavelength light emitting devices and so on.

  2. Thickness dependent structural, optical and electrical properties of Se85In12Bi3 nanochalcogenide thin films

    Science.gov (United States)

    Tripathi, Ravi P.; Zulfequar, M.; Khan, Shamshad A.

    2018-04-01

    Our aim is to study the thickness dependent effects on structure, electrical and optical properties of Se85In12Bi3 nanochalcogenide thin films. Bulk alloy of Se85In12Bi3 was synthesized by melt-quenching technique. The amorphous as well as glassy nature of Se85In12Bi3 chalcogenide was confirmed by non-isothermal Differential Scanning Calorimetry (DSC) measurements. The nanochalcogenide thin films of thickness 30, 60 and 90 nm were prepared on glass/Si wafer substrate using Physical Vapour Condensation Technique (PVCT). From XRD studies it was found that thin films have amorphous texture. The surface morphology and particle size of films were studied by Field Emission Scanning Electron Microscope (FESEM). From optical studies, different optical parameters were estimated for Se85In12Bi3 thin films at different thickness. It was found that the absorption coefficient (α) and extinction coefficient (k) increases with photon energy and decreases with film thickness. The optical absorption process followed the rule of indirect transitions and optical band gap were found to be increase with film thickness. The value of Urbach energy (Et) and steepness parameter (σ) were also calculated for different film thickness. For electrical studies, dc-conductivity measurement was done at different temperature and activation energy (ΔEc) were determined and found to be increase with film thickness.

  3. Factors influencing formation of highly dispersed BaTiO3 nanospheres with uniform sizes in static hydrothermal synthesis

    International Nuclear Information System (INIS)

    Gao, Jiabing; Shi, Haiyue; Dong, Huina; Zhang, Rui; Chen, Deliang

    2015-01-01

    Highly dispersed BaTiO 3 nanospheres with uniform sizes have important applications in micro/nanoscale functional devices. To achieve well-dispersed spherical BaTiO 3 nanocrystals, we carried out as reported in this paper the systematic investigation on the factors that influence the formation of BaTiO 3 nanospheres by the static hydrothermal process, including the NaOH concentrations [NaOH], molar Ba/Ti ratios (R Ba/Ti ), hydrothermal temperatures, and durations, with an emphasis on understanding the related mechanisms. Barium nitrate and TiO 2 sols derived from tetrabutyl titanate were used as the starting materials. The as-synthesized BaTiO 3 samples were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, thermogravimetry, differential thermal analysis, and FT-IR spectra. The highly dispersed BaTiO 3 nanospheres (76 ± 13 nm) were achieved under the optimum hydrothermal conditions at 200 °C for 10 h: [NaOH] = 2.0 mol L −1 and R Ba/Ti  = 1.5. Higher NaOH concentrations, higher Ba/Ti ratios, higher hydrothermal temperatures, and longer hydrothermal durations are favorable in forming BaTiO 3 nanospheres with larger fractions of tetragonal phase and higher yields; but too long hydrothermal durations resulted in abnormal growth and reduced the uniformity in particle sizes. The possible formation mechanisms for BaTiO 3 nanocrystals under the static hydrothermal conditions were investigated

  4. Chemical synthesis of Fe{sub 2}O{sub 3} thin films for supercapacitor application

    Energy Technology Data Exchange (ETDEWEB)

    Kulal, P.M.; Dubal, D.P.; Lokhande, C.D. [Holography and Material Research Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, M.S. (India); Fulari, V.J., E-mail: vijayfulari@gmail.com [Holography and Material Research Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, M.S. (India)

    2011-02-03

    Research highlights: > Simple chemical synthesis of Fe{sub 2}O{sub 3}. > Formation of amorphous and hydrous Fe{sub 2}O{sub 3}. > Potential candidate for supercapacitors. - Abstract: Fe{sub 2}O{sub 3} thin films have been prepared by novel chemical successive ionic layer adsorption and reaction (SILAR) method. Further these films were characterized for their structural, morphological and optical properties by means of X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrum, scanning electron microscopy (SEM), wettability test and optical absorption studies. The XRD pattern showed that the Fe{sub 2}O{sub 3} films exhibit amorphous in nature. Formation of iron oxide compound was confirmed from FTIR studies. The optical absorption showed existence of direct optical band gap of energy 2.2 eV. Fe{sub 2}O{sub 3} film surface showed superhydrophilic nature with water contact angle less than 10{sup o}. The supercapacitive properties of Fe{sub 2}O{sub 3} thin film investigated in 1 M NaOH electrolyte showed supercapacitance of 178 F g{sup -1} at scan rate 5 mV/s.

  5. Host thin films incorporating nanoparticles

    Science.gov (United States)

    Qureshi, Uzma

    The focus of this research project was the investigation of the functional properties of thin films that incorporate a secondary nanoparticulate phase. In particular to assess if the secondary nanoparticulate material enhanced a functional property of the coating on glass. In order to achieve this, new thin film deposition methods were developed, namely use of nanopowder precursors, an aerosol assisted transport technique and an aerosol into atmospheric pressure chemical vapour deposition system. Aerosol assisted chemical vapour deposition (AACVD) was used to deposit 8 series of thin films on glass. Five different nanoparticles silver, gold, ceria, tungsten oxide and zinc oxide were tested and shown to successfully deposit thin films incorporating nanoparticles within a host matrix. Silver nanoparticles were synthesised and doped within a titania film by AACVD. This improved solar control properties. A unique aerosol assisted chemical vapour deposition (AACVD) into atmospheric pressure chemical vapour deposition (APCVD) system was used to deposit films of Au nanoparticles and thin films of gold nanoparticles incorporated within a host titania matrix. Incorporation of high refractive index contrast metal oxide particles within a host film altered the film colour. The key goal was to test the potential of nanopowder forms and transfer the suspended nanopowder via an aerosol to a substrate in order to deposit a thin film. Discrete tungsten oxide nanoparticles or ceria nanoparticles within a titanium dioxide thin film enhanced the self-cleaning and photo-induced super-hydrophilicity. The nanopowder precursor study was extended by deposition of zinc oxide thin films incorporating Au nanoparticles and also ZnO films deposited from a ZnO nanopowder precursor. Incorporation of Au nanoparticles within a VO: host matrix improved the thermochromic response, optical and colour properties. Composite VC/TiC and Au nanoparticle/V02/Ti02 thin films displayed three useful

  6. Highly piezoelectric BaTiO3 nanorod bundle arrays using epitaxially grown TiO2 nanomaterials.

    Science.gov (United States)

    Jang, Seon-Min; Yang, Su Chul

    2018-06-08

    Low-dimensional piezoelectric nanostructures such as nanoparticles, nanotubes, nanowires, nanoribbons and nanosheets have been developed for potential applications as energy harvesters, tunable sensors, functional transducers and low-power actuators. In this study, lead-free BaTiO 3 nanorod bundle arrays (NBA) with highly piezoelectric properties were successfully synthesized on fluorine-doped tin oxide (FTO) substrate via a two-step process consisting of TiO 2 epitaxial growth and BaTiO 3 conversion. Through the TiO 2 epitaxial growth on FTO substrate, (001) oriented TiO 2 nanostructures formed vertically-aligned NBA with a bundle diameter of 80 nm and an aspect ratio of six. In particular, chemical etching of the TiO 2 NBA was conducted to enlarge the surface area for effective Ba 2+ ion diffusion during the perovskite conversion process from TiO 2 to BaTiO 3 . The final structure of perovskite BaTiO 3 NBA was found to exhibit a feasible piezoelectric response of 3.56 nm with a clear phase change of 180° from the single BaTiO 3 bundle, by point piezoelectric forced microscopy (PFM) analysis. Consequently, highly piezoelectric NBA could be a promising nanostructure for various nanoscale electronic devices.

  7. Highly piezoelectric BaTiO3 nanorod bundle arrays using epitaxially grown TiO2 nanomaterials

    Science.gov (United States)

    Jang, Seon-Min; Yang, Su Chul

    2018-06-01

    Low-dimensional piezoelectric nanostructures such as nanoparticles, nanotubes, nanowires, nanoribbons and nanosheets have been developed for potential applications as energy harvesters, tunable sensors, functional transducers and low-power actuators. In this study, lead-free BaTiO 3 nanorod bundle arrays (NBA) with highly piezoelectric properties were successfully synthesized on fluorine-doped tin oxide (FTO) substrate via a two-step process consisting of TiO2 epitaxial growth and BaTiO3 conversion. Through the TiO2 epitaxial growth on FTO substrate, (001) oriented TiO2 nanostructures formed vertically-aligned NBA with a bundle diameter of 80 nm and an aspect ratio of six. In particular, chemical etching of the TiO2 NBA was conducted to enlarge the surface area for effective Ba2+ ion diffusion during the perovskite conversion process from TiO2 to BaTiO3. The final structure of perovskite BaTiO3 NBA was found to exhibit a feasible piezoelectric response of 3.56 nm with a clear phase change of 180° from the single BaTiO3 bundle, by point piezoelectric forced microscopy (PFM) analysis. Consequently, highly piezoelectric NBA could be a promising nanostructure for various nanoscale electronic devices.

  8. Characterization of nanocrystalline cadmium telluride thin films ...

    Indian Academy of Sciences (India)

    Unknown

    tion method, successive ionic layer adsorption and reaction (SILAR), are described. For deposition of CdTe thin films ... By conducting several trials optimization of the adsorption, reaction and rinsing time duration for CdTe thin film .... The electrical resistivity of CdTe films was studied in air. Figure 3 shows the variation of log ...

  9. Optimization of excess Bi doping to enhance ferroic orders of spin casted BiFeO{sub 3} thin film

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Surbhi; Gupta, Vinay, E-mail: drguptavinay@gmail.com [Department of Physics and Astrophysics, University of Delhi, Delhi (India); Tomar, Monika [Department of Physics, Miranda Housea, University of Delhi, Delhi (India); James, A. R. [Defence Metallurgical Research Laboratory, Hyderabad (India); Pal, Madhuparna; Guo, Ruyan; Bhalla, Amar [Department of Electrical and Computer Engineering, College of Engineering, University of Texas at SanAntonio, San Antonio 78249 (United States)

    2014-06-21

    Multiferroic Bismuth Ferrite (BiFeO{sub 3}) thin films with varying excess bismuth (Bi) concentration were grown by chemical solution deposition technique. Room temperature multiferroic properties (ferromagnetism, ferroelectricity, and piezoelectricity) of the deposited BiFeO{sub 3} thin films have been studied. High resolution X-ray diffraction and Raman spectroscopy studies reveal that the dominant phases formed in the prepared samples change continuously from a mixture of BiFeO{sub 3} and Fe{sub 2}O{sub 3} to pure BiFeO{sub 3} phase and, subsequently, to a mixture of BiFeO{sub 3} and Bi{sub 2}O{sub 3} with increase in the concentration of excess Bi from 0% to 15%. BiFeO{sub 3} thin films having low content (0% and 2%) of excess Bi showed the traces of ferromagnetic phase (γ-Fe{sub 2}O{sub 3}). Deterioration in ferroic properties of BiFeO{sub 3} thin films is also observed when prepared with higher content (15%) of excess Bi. Single-phased BiFeO{sub 3} thin film prepared with 5% excess Bi concentration exhibited the soft ferromagnetic hysteresis loops and ferroelectric characteristics with remnant polarization 4.2 μC/cm{sup 2} and saturation magnetization 11.66 emu/g. The switching of fine spontaneous domains with applied dc bias has been observed using piezoresponse force microscopy in BiFeO{sub 3} thin films having 5% excess Bi. The results are important to identify optimum excess Bi concentration needed for the formation of single phase BiFeO{sub 3} thin films exhibiting the improved multiferroic properties.

  10. Nb3Al thin film deposition for low-noise terahertz electronics

    International Nuclear Information System (INIS)

    Dochev, D; Pavolotsky, A B; Belitsky, V; Olofsson, H

    2008-01-01

    Higher energy gap superconducting materials were always interesting for low-noise mixer applications such as superconductor-insulator-superconductor tunnel junctions (SIS) and hot-electron bolometer (HEB) used in sub-millimeter and terahertz parts of electro-magnetic spectrum. Here, we report a novel approach for producing Nb 3 Al thin film by co-sputtering from two confocally arranged Nb and Al dc-magnetrons onto substrate heated up to 830 deg. C. Characterization of the deposited films revealed presence of the A15 phase and measured critical temperature was up to 15.7 K with the transition width 0.2-0.3 K for a 300 nm thick film. We measured the film critical magnetic field and studied influence of annealing on the film properties. We have investigated compositional depth profile of the deposited films by spectroscopy of reflected electrons

  11. Gas Sensing Properties of Metal Doped WO3 Thin Film Sensors Prepared by Pulsed Laser Deposition and DC Sputtering Process

    Science.gov (United States)

    Bhuiyan, Md. Mosharraf Hossain; Ueda, Tsuyoshi; Ikegami, Tomoaki; Ebihara, Kenji

    2006-10-01

    Tungsten trioxide (WO3) thin films gas sensors were prepared by the KrF excimer pulsed laser deposition (PLD) method. The films were prepared on the quartz glass, silicon and also on the Al2O3 sensor substrates with platinum interdigitated electrodes. The effect of doping of the platinum (Pt), palladium (Pd) or gold (Au) on the WO3 thin film was also investigated. These metals were doped to the WO3 thin film by the DC sputtering process during the PLD. The substrate temperature and the oxygen pressure were 400 °C and 100 mTorr, respectively, during the deposition. The films were characterized by atomic force microscopy (AFM) and X-ray diffraction (XRD). The sensitivity of the prepared sensors to 60 ppm NO gas was examined using the two terminal resistance method in a chamber at atmospheric pressure and operating temperatures of 25-350 °C. The sensitivity of the WO3 thin films doped with Pt, Pd, or Au was found to be higher than that of the undoped WO3 thin film.

  12. Novel chemical analysis for thin films

    International Nuclear Information System (INIS)

    Usui, Toshio; Kamei, Masayuki; Aoki, Yuji; Morishita, Tadataka; Tanaka, Shoji

    1991-01-01

    Scanning electron microscopy and total-reflection-angle X-ray spectroscopy (SEM-TRAXS) was applied for fluorescence X-ray analysis of 50A- and 125A-thick Au thin films on Si(100). The intensity of the AuM line (2.15 keV) emitted from the Au thin films varied as a function of the take-off angle (θ t ) with respect to the film surface; the intensity of AuM line from the 125A-thick Au thin film was 1.5 times as large as that of SiK α line (1.74 keV) emitted from the Si substrate when θ t = 0deg-3deg, in the vicinity of a critical angle for total external reflection of the AuM line at Si (0.81deg). In addition, the intensity of the AuM line emitted from the 50A-thick Au thin film was also sufficiently strong for chemical analysis. (author)

  13. Substrate decoration for improvement of current-carrying capabilities of YBa2Cu3Ox thin films

    International Nuclear Information System (INIS)

    Khoryushin, Alexey V.; Mozhaev, Peter B.; Mozhaeva, Julia E.; Bdikin, Igor K.; Zhao, Yue; Andersen, Niels H.; Jacobsen, Claus S.; Hansen, Jørn Bindslev

    2013-01-01

    Highlights: ► Effects of substrate decoration on properties of YBCO thin films were studied. ► Y 2 O 3 nanoparticles, ultra-thin Y 2 O 3 and Y:ZrO 2 layers were used as decoration layer. ► Decoration improves j C (5 T and 50 K) up to 0.97 MA/cm 2 vs. 0.76 MA/cm 2 for a reference film. ► Ultra-thin layer of yttria and yttria nanoparticles have a similar effect on YBCO. ► Y 2 O 3 decoration results in power law coefficient α = 0.3 vs. α = 0.4 for a reference film. -- Abstract: The effects of substrate decoration with yttria and Y:ZrO 2 on the structural and electrical properties of the YBa 2 Cu 3 O x (YBCO) thin films are studied. The films were deposited on (LaAlO 3 ) 3 –(Sr 2 AlTaO 8 ) 7 substrates by pulsed laser deposition. Two different structures of decoration layer were applied, a template layer of nanoparticles and an uniform ultra-thin layer. Significant improvement of current-carrying capabilities was observed, especially at high external magnetic fields. Structural studies of these films reveal the presence of extended linear defects in the YBCO matrix. The formation of these structures is attributed to seeding of randomly oriented YBCO grains due to suppression of epitaxy in the very beginning of the deposition. The films of both kinds of decoration layers show nearly the same improvement of j C over the reference film at 77 and 50 K: j C (5T and 50 K) reaches 0.92 and 0.97 MA/cm 2 for uniform and template decoration layers. At 5 and 20 K the effect of template decoration layers is more beneficial: j C (5T and 20 K) values are 3.5 and 4.1 MA/cm 2 , j C (5T and 5 K) values are 6.4 and 7.9 MA/cm 2 , for uniform and template decoration layers, respectively

  14. Indium Sulfide and Indium Oxide Thin Films Spin-Coated from Triethylammonium Indium Thioacetate Precursor for n-Channel Thin Film Transistor

    Energy Technology Data Exchange (ETDEWEB)

    Tung, Duy Dao; Jeong, Hyun Dam [Chonnam Natioal University, Gwangju (Korea, Republic of)

    2014-09-15

    The In{sub 2}S{sub 3} thin films of tetragonal structure and In{sub 2}O{sub 3} films of cubic structure were synthesized by a spin coating method from the organometallic compound precursor triethylammonium indium thioacetate ([(Et){sub 3}NH]+ [In(SCOCH{sub 3}){sub 4}]''-; TEA-InTAA). In order to determine the electron mobility of the spin-coated TEA-InTAA films, thin film transistors (TFTs) with an inverted structure using a gate dielectric of thermal oxide (SiO{sub 2}) was fabricated. These devices exhibited n-channel TFT characteristics with a field-effect electron mobility of 10.1 cm''2 V''-1s''-1 at a curing temperature of 500 o C, indicating that the semiconducting thin film material is applicable for use in low-cost, solution-processed printable electronics.

  15. Critical behavior of ferromagnetic La0.7Sr0.3CoO3 thin films

    International Nuclear Information System (INIS)

    Schwarz, T.

    2007-07-01

    The present thesis concentrates on the critical behavior of ferromagnetic La 0.7 Sr 0.3 CoO 3 thin films (LSCO) close to the magnetic phase transition. The LSCO thin films were prepared by pulsed laser deposition and optimized with respect to their structural and magnetic properties. For the characterization of the structural and magnetic characteristics various methods were used. By means of X-ray diffraction and electron microscopy the crystallinity and microstructure of the epitaxial films were examined, respectively. The analysis of the chemical composition was accomplished by Rutherford backscattering and energy dispersive X-ray diffraction (EDX). Parallel to the investigations of the LSCO films a low-temperature measuring system for electrical measurements in magnetic fields up to 8 T in a temperature range from 1.5 K to 300 K was developed and built up including the necessary control and measuring software. The central point of this work was dedicated to the characterization of the magnetic characteristics of the LSCO films. In comparison, single crystals and polycrystalline bulk samples were also available. At these samples temperature-dependent and isothermal magnetization measurements were accomplished by a SQUID magnetometer. To determine the critical behavior of the samples the critical exponents of the susceptibility and the spontaneous magnetization in the proximity of the ferromagnetic phase transition were determined. For the exact determination of the critical exponents from the experimental data an evaluation routine in Matlab on basis of the Arrott representation method was used. In addition to the investigations of the critical behavior, electrical transportation measurements and neutron reflection measurements with spin-polarized neutrons were performed. The investigations of this work show that, in contrast to the critical behavior of single-crystal LSCO volume samples where a three-dimensional Heisenberg behavior could be observed, the

  16. NMR characterization of thin films

    Science.gov (United States)

    Gerald II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2010-06-15

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  17. NMR characterization of thin films

    Science.gov (United States)

    Gerald, II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2008-11-25

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  18. Photoelectrochemical Performance Observed in Mn-Doped BiFeO3 Heterostructured Thin Films

    Directory of Open Access Journals (Sweden)

    Hao-Min Xu

    2016-11-01

    Full Text Available Pure BiFeO3 and heterostructured BiFeO3/BiFe0.95Mn0.05O3 (5% Mn-doped BiFeO3 thin films have been prepared by a chemical deposition method. The band structures and photosensitive properties of these films have been investigated elaborately. Pure BiFeO3 films showed stable and strong response to photo illumination (open circuit potential kept −0.18 V, short circuit photocurrent density was −0.023 mA·cm−2. By Mn doping, the energy band positions shifted, resulting in a smaller band gap of BiFe0.95Mn0.05O3 layer and an internal field being built in the BiFeO3/BiFe0.95Mn0.05O3 interface. BiFeO3/BiFe0.95Mn0.05O3 and BiFe0.95Mn0.05O3 thin films demonstrated poor photo activity compared with pure BiFeO3 films, which can be explained by the fact that Mn doping brought in a large amount of defects in the BiFe0.95Mn0.05O3 layers, causing higher carrier combination and correspondingly suppressing the photo response, and this negative influence was more considerable than the positive effects provided by the band modulation.

  19. Characterization of nanostructured Mn3O4 thin films grown by SILAR method at room temperature

    International Nuclear Information System (INIS)

    Ubale, A.U.; Belkhedkar, M.R.; Sakhare, Y.S.; Singh, Arvind; Gurada, Chetan; Kothari, D.C.

    2012-01-01

    A novel successive ionic layer adsorption and reaction method has been successfully employed to grow nanostructured conducting nearly transparent thin films of Mn 3 O 4 on to glass substrates at room temperature using MnCl 2 and NaOH as cationic and anionic precursors. The structural and morphological characterizations of the as deposited Mn 3 O 4 films have been carried out by means of X-ray diffraction (XRD), Field Emission Scanning Electron Micrograph (FESEM), EDAX, Atomic Fore Microscopy (AFM) and Fourier Transform Infrared Spectrum (FTIR) analysis. The optical absorption and electrical resistivity measurements were carried out to investigate optical band gap and activation energy of Mn 3 O 4 films deposited by SILAR method. The optical band gap and activation energy of the as deposited film is found to be 2.70 and 0.14 eV respectively. The thermo-emf measurements of Mn 3 O 4 thin film confirm its p-type semiconducting nature. Highlights: ► Nanostructured Mn 3 O 4 thin film is prepared by SILAR method at room temperature. ► The film is nanocrystalline with orthorhombic structure of Mn 3 O 4 . ► The XRD, FTIR, FESEM, EDX and AFM characterization confirms nanocrystalline nature. ► Optical band gap, electrical resistivity and activation energy of film is reported. ► A thermo-emf measurement confirms p-type conductivity of Mn 3 O 4 films.

  20. THE APPLICATION OF STEREOLOGY METHOD FOR ESTIMATING THE NUMBER OF 3D BaTiO3 – CERAMIC GRAINS CONTACT SURFACES

    Directory of Open Access Journals (Sweden)

    Vojislav V Mitić

    2011-05-01

    Full Text Available Methods of stereological study are of great importance for structural research of electronic ceramic materials including BaTiO3-ceramic materials. The broad application of ceramics, based on barium-titanate, in advanced electronics nowadays demands a constant research of its structure, that through the correlation structureproperties, a fundamental in the basic materials properties prognosis triad (technology-structure-properties, leads to further prognosis and properties design of these ceramics. Microstructure properties of BaTiO3- ceramic material, expressed in grains' boundary contact, are of basic importance for electric properties of this material, particularly the capacity. In this paper, a significant step towards establishing control under capacitive properties of BaTiO3-ceramics is being done by estimating the number of grains contact surfaces. Defining an efficient stereology method for estimating the number of BaTiO3-ceramic grains contact surfaces, we have started from a mathematical model of mutual grains distribution in the prescribed volume of BaTiO3-ceramic sample. Since the real microstructure morphology of BaTiO3-ceramics is in some way disordered, spherical shaped grains, using computer-modelling methods, are approximated by polyhedra with a great number of small convex polygons. By dividing the volume of BaTiO3-ceramic sample with the definite number of parallel planes, according to a given pace, into the intersection plane a certain number of grains contact surfaces are identified. According to quantitative estimation of 2D stereological parameters the modelled 3D internal microstructure is obtained. Experiments were made by using the scanning electronic microscopy (SEM method with the ceramic samples prepared under pressing pressures up to 150 MPa and sintering temperature up to 1370°C while the obtained microphotographs were used as a base of confirming the validity of presented stereology method. This paper, by applying

  1. Photoluminescence properties of perovskite multilayer thin films

    Energy Technology Data Exchange (ETDEWEB)

    Macario, Leilane Roberta; Longo, Elson, E-mail: leilanemacario@gmail.com [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil); Mazzo, Tatiana Martelli [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil); Bouquet, Valerie; Deputier, Stephanie; Ollivier, Sophie; Guilloux-Viry, Maryline [Universite de Rennes (France)

    2016-07-01

    Full text: The knowledge of the optical properties of thin films is important in many scientific, technological and industrial applications of thin films such as photoconductivity, solar energy, photography, and numerous other applications [1]. In this study, perovskite type oxides were grown by pulsed laser deposition [2] in order to obtain thin films with applicable optical properties. The LaNiO{sub 3} (LN), BaTiO{sub 3} (BT) and KNbO{sub 3} (KNb) targets were prepared by solid-state reaction. The X-ray Diffraction revealed the presence of the desired phases, containing the elements of interest in the targets and in the thin films that were produced. The LN, BT and KNb thin films were polycrystalline and the corresponding diffraction peaks were indexed in the with JCPDS cards n. 00-033-0711, n. 00-005-0626, and n. 00-009-0156, respectively. The multilayers films were polycrystalline. The majority of the micrographs obtained by scanning electron microscopy presented films with a thickness from 100 to 400 nm. The photoluminescent (PL) emission spectra of thin films show different broad bands that occupies large region of the visible spectrum, ranging from about 300-350 to 600-650 nm of the electromagnetic spectrum. The PL emission is associated with the order-disorder structural, even small structural changes can modify the interactions between electronic states. The structural disorder results in formation of new energy levels in the forbidden region. The proximity or distance of these new energy levels formed in relation to valence band and to the conduction band results in PL spectra located at higher or lower energies. These interactions change the electronic states which can be influenced by defects, particularly the interface defects between the layers of the thin films. The presence of defects results in changes in the broad band matrix intensity and in displacement of the PL emission maximum. (author)

  2. Antisolvent-assisted powder engineering for controlled growth of hybrid CH3NH3PbI3 perovskite thin films

    Directory of Open Access Journals (Sweden)

    Yong Chan Choi

    2017-02-01

    Full Text Available We develop antisolvent-assisted powder engineering for the controlled growth of hybrid inorganic-organic CH3NH3PbI3 (MAPbI3 perovskite thin films. The powders, which are used as the precursors for solution processing, are synthesized by pouring a MAPbI3 precursor solution into various antisolvents, such as dichloromethane, chloroform, diethyl ether, and toluene. Two types of powders having different colors are obtained, depending on the antisolvent used. The choice of the antisolvent used for synthesizing the powders strongly influences not only the phases of the powders but also the morphology and structure of the thin films subsequently fabricated by solution processing. This, in turn, affects the photovoltaic performance.

  3. Handbook of thin film technology

    CERN Document Server

    Frey, Hartmut

    2015-01-01

    “Handbook of Thin Film Technology” covers all aspects of coatings preparation, characterization and applications. Different deposition techniques based on vacuum and plasma processes are presented. Methods of surface and thin film analysis including coating thickness, structural, optical, electrical, mechanical and magnetic properties of films are detailed described. The several applications of thin coatings and a special chapter focusing on nanoparticle-based films can be found in this handbook. A complete reference for students and professionals interested in the science and technology of thin films.

  4. Preparation and evaluation of Mn3GaN1-x thin films with controlled N compositions

    Science.gov (United States)

    Ishino, Sunao; So, Jongmin; Goto, Hirotaka; Hajiri, Tetsuya; Asano, Hidefumi

    2018-05-01

    Thin films of antiperovskite Mn3GaN1-x were grown on MgO (001) substrates by reactive magnetron sputtering, and their structural, magnetic, and magneto-optical properties were systematically investigated. It was found that the combination of the deposition rate and the N2 gas partial pressure could produce epitaxial films with a wide range of N composition (N-deficiency) and resulting c/a values (0.93 - 1.0). While the films with c/a = 0.992 - 1.0 were antiferromagnetic, the films with c/a = 0.93 - 0.989 showed perpendicular magnetic anisotropy (PMA) with the maximum PMA energy up to 1.5×106 erg/cm3. Systematic dependences of the energy spectra of the polar Kerr signals on the c/a ratio were observed, and the Kerr ellipticity was as large as 2.4 deg. at 1.9 eV for perpendicularly magnetized ferromagnetic thin films with c/a = 0.975. These results highlight that the tetragonal distortion plays an important role in magnetic and magneto-optical properties of Mn3GaN1-x thin films.

  5. Preparation and characterization of Cu2SnS3 thin films by electrodeposition

    Science.gov (United States)

    Patel, Biren; Narasimman, R.; Pati, Ranjan K.; Mukhopadhyay, Indrajit; Ray, Abhijit

    2018-05-01

    Cu2SnS3 thin films were electrodeposited on F:SnO2/Glass substrates at room temperature by using aqueous solution. Copper and tin were first electrodeposited from single bath and post annealed in the presence of sulphur atmosphere to obtain the Cu2SnS3 phase. The Cu2SnS3 phase with preferred orientation along the (112) crystal direction grows to greater extent by the post annealing of the film. Raman analysis confirms the monoclinic crystal structure of Cu2SnS3 with principle mode of vibration as A1 (symmetric breathing mode) corresponding to the band at 291 cm-1. It also reveals the benign coexistence of orthorhombic Cu3SnS4 and Cu2SnS7 phases. Optical properties of the film show direct band gap of 1.25 eV with a high absorption coefficient of the order of 104 cm-1 in the visible region. Photo activity of the electrodeposited film was established in two electrode photoelectro-chemical cell, where an open circuit voltage of 91.6 mV and a short circuit current density of 10.6 µA/cm2 were recorded. Fabrication of Cu2SnS3 thin film heterojunction solar cell is underway.

  6. Giant Polarization Rotation in BiFeO3/SrTiO3 Thin Films.

    Science.gov (United States)

    Langner, M. C.; Chu, Y. H.; Martin, L. M.; Gajek, M.; Ramesh, R.; Orenstein, J.

    2008-03-01

    We use optical second harmonic generation to probe dynamics of the ferroelectric polarization in (111) oriented BiFeO3 thin films grown on SrTiO3 substrates. The second harmonic response indicates 3m point group symmetry and is consistent with a spontaneous polarization normal to the surface of the film. We measure large changes in amplitude and lowering of symmetry, consistent with polarization rotation, when modest electric fields are applied in the plane of the film. At room temperature the rotation is an order of magnitude larger than expected from reported values of the dielectric constant and increases further (as 1/T) as temperature is lowered. We propose a substrate interaction model to explain these results.

  7. YIG: Bi2O3 Nanocomposite Thin Films for Magnetooptic and Microwave Applications

    Directory of Open Access Journals (Sweden)

    M. Nur-E-Alam

    2015-01-01

    Full Text Available Y3Fe5O12-Bi2O3 composite thin films are deposited onto Gd3Ga5O12 (GGG substrates and their annealing crystallization regimes are optimized (in terms of both process temperatures and durations to obtain high-quality thin film layers possessing magnetic properties attractive for a range of technological applications. The amount of bismuth oxide content introduced into these nanocomposite-type films is controlled by adjusting the RF power densities applied to both Y3Fe5O12 and Bi2O3 sputtering targets during the cosputtering deposition processes. The measured material properties of oven-annealed YIG-Bi2O3 films indicate that cosputtering of YIG-Bi2O3 composites can provide the flexibility of application-specific YIG layers fabrication of interest for several existing, emerging, and also frontier technologies. Experimental results demonstrate large specific Faraday rotation (of more than 1°/µm at 532 nm, achieved simultaneously with low optical losses in the visible range and very narrow peak-to-peak ferromagnetic resonance linewidth of around ΔHpp= 6.1 Oe at 9.77 GHz.

  8. Ultraviolet emitting (Y1-xGd x)2O3thin films deposited by radio frequency magnetron sputtering; structure-property-thin film processing relationships

    International Nuclear Information System (INIS)

    Fowlkes, J.D.; Fitz-Gerald, J.M.; Rack, P.D.

    2007-01-01

    The effects that the oxygen partial pressure, substrate temperature and annealing temperature have on the cathodoluminescence (CL) efficiency of radio frequency magnetron sputter deposited Gd-doped Y 2 O 3 thin films is investigated. Furthermore these sputtering parameters are correlated to the degree of crystallinity, the phases present (cubic (α) versus monoclinic (β) Y 2 O 3 ), and the stoichiometry of the thin films. Films deposited at room temperature (RT) did not CL, however, the films were activated by a post-deposition anneal at 1273 K for 6 h. Films deposited at 873 K had a very low CL efficiency which was significantly enhanced by a post-deposition anneal. For RT deposited films the external CL efficiency increased with increasing oxygen partial pressure for the range studied, however the opposite trend was observed for the 873 K deposited films. Examination of the morphology and grain size of the high temperature deposited films revealed that the average grain size increased with decreasing partial pressure and the observed increase in the external CL efficiency was attributed to enhanced anomalous diffraction. An intrinsic CL efficiency term was determined to circumvent the effects of the enhanced anomalous diffraction, and the CL efficiency was correlated to the integrated intensity of the (222) of the cubic α-Y 2 O 3 phase

  9. Stabilization and enhanced energy gap by Mg doping in ε-phase Ga2O3 thin films

    Directory of Open Access Journals (Sweden)

    Xiaoyu Bi

    2018-02-01

    Full Text Available Mg-doped Ga2O3 thin films with different doping concentrations were deposited on sapphire substrates using laser molecular beam epitaxy (L-MBE technique. X-ray diffraction (XRD, x-ray photoelectron spectroscopy (XPS and ultraviolet-visible (UV-vis absorption spectrum were used to characterize the crystal structure and optical properties of the as-grown films. Compared to pure Ga2O3 thin film, the Mg-doped thin films have transformed from the most stable β-phase into ε-phase. The absorption edge shifted to about 205 nm and the optical bandgap increased to ∼ 6 eV. These properties reveal that Mg-doped Ga2O3 films may have potential applications in the field of deep ultraviolet optoelectronic devices, such as deep ultraviolet photodetectors, short wavelength light emitting devices and so on.

  10. Rare Earth Oxide Thin Films

    CERN Document Server

    Fanciulli, Marco

    2007-01-01

    Thin rare earth (RE) oxide films are emerging materials for microelectronic, nanoelectronic, and spintronic applications. The state-of-the-art of thin film deposition techniques as well as the structural, physical, chemical, and electrical properties of thin RE oxide films and of their interface with semiconducting substrates are discussed. The aim is to identify proper methodologies for the development of RE oxides thin films and to evaluate their effectiveness as innovative materials in different applications.

  11. Thin-film solar cells

    International Nuclear Information System (INIS)

    Aberle, Armin G.

    2009-01-01

    The rapid progress that is being made with inorganic thin-film photovoltaic (PV) technologies, both in the laboratory and in industry, is reviewed. While amorphous silicon based PV modules have been around for more than 20 years, recent industrial developments include the first polycrystalline silicon thin-film solar cells on glass and the first tandem solar cells based on stacks of amorphous and microcrystalline silicon films ('micromorph cells'). Significant thin-film PV production levels are also being set up for cadmium telluride and copper indium diselenide.

  12. Nanocomposite Thin Film of Poly(3-aminobenzoic acid and Multiwalled Carbon Nanotubes Fabricated through an Electrochemical Method

    Directory of Open Access Journals (Sweden)

    Paphawadee Netsuwan

    2014-01-01

    Full Text Available The composite thin films of poly(3-aminobenzoic acid (PABA and multiwalled carbon nanotubes (MWNTs are successfully fabricated through an electrochemical method. The composite mixtures containing 50 mM of 3-aminobenzoic acid with various concentrations of MWNTs (1.0, 2.5, 5.0, 7.5, and 10 mg/mL in 0.5 M H2SO4 were prepared and used in this study. Cyclic voltammetry (CV was used for fabrication and monitoring the electropolymerization of the composite thin films with potential range of 0 to 1100 mV for 5 cycles at scan rate of 20 mV/s on indium tin oxide- (ITO-coated glass substrate. UV-vis absorption spectroscopy, atomic force microscopy (AFM, and scanning electron microscopy (SEM techniques were employed to characterize the obtained composite thin films. It was found that MWNTs can enhance the peak current of CV traces of the PABA/MWNTs composite thin films without affecting the UV-vis absorption spectra. The surface morphology of the thin films can be studied using AFM and SEM techniques.

  13. Photolithographically patterened thin-film multilayer devices of YBa2Cu3O7-x

    International Nuclear Information System (INIS)

    Kingston, J.J.; Wellstood, F.C.; Quan, D.; Clarke, J.

    1990-09-01

    We have fabricated thin-film YBa 2 Cu 3 O 7-x -SrTiO 3 -YBa 2 Cu 3 O 7-x multilayer interconnect structures in which each in situ laser-deposited film is independently patterned by photolithography. In particular, we have constructed the two key components necessary for a superconducting multilayer interconnect technology, crossovers and window contacts. As a further demonstration of the technology, we have fabricated a thin-film flux transformer, suitable for use with a Superconducting QUantum Interference Device (SQUID), that includes a ten-turn input coil with 6μm linewidth. Transport measurements showed that the critical temperature was 87K and the critical current was 135 μA at 82K. 7 refs., 6 figs

  14. Growth of (100)-highly textured BaBiO{sub 3} thin films on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ferreyra, C. [GIyA and INN, CNEA, Av. Gral Paz 1499, 1650 San Martín, Buenos Aires (Argentina); Departamento de Física, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 1, Ciudad Universitaria, Buenos Aires (Argentina); Marchini, F. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Departamento de Química Inorgánica, Analítica y Química-Física, INQUIMAE-CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, Buenos Aires (Argentina); Granell, P. [INTI, CMNB, Av. Gral Paz 5445, B1650KNA San Martín, Buenos Aires (Argentina); Golmar, F. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); INTI, CMNB, Av. Gral Paz 5445, B1650KNA San Martín, Buenos Aires (Argentina); Escuela de Ciencia y Tecnología, UNSAM, Campus Miguelete, 1650 San Martín, Buenos Aires (Argentina); Albornoz, C. [GIyA and INN, CNEA, Av. Gral Paz 1499, 1650 San Martín, Buenos Aires (Argentina); and others

    2016-08-01

    We report on the growth and characterization of non-epitaxial but (100)-highly textured BaBiO{sub 3} thin films on silicon substrates. We have found the deposition conditions that optimize the texture, and show that the textured growth is favoured by the formation of a BaO layer at the first growth stages. X-ray diffraction Φ-scans, together with the observation that the same textured growth is found on films grown on Pt and SiO{sub 2} buffered Si, demonstrate the absence of epitaxy. Finally, we have shown that our (100)-oriented BaBiO{sub 3} films can be used as suitable buffers for the growth of textured heterostructures on silicon, which could facilitate the integration of potential devices with standard electronics. - Highlights: • BaBiO{sub 3} thin films were grown on Si substrates and characterized. • Films prepared using optimized conditions are highly textured in the (100) direction. • The absence of in-plane texture was demonstrated by X-ray diffraction. • Our films are suitable buffers for the growth of (100)-textured oxide heterostructures.

  15. Process for forming thin film, heat treatment process of thin film sheet, and heat treatment apparatus therefor

    International Nuclear Information System (INIS)

    Watanabe, S.

    1984-01-01

    The invention provides a process for forming a magnetic thin film on a base film, a heat treatment process of a thin film sheet consisting of the base film and the magnetic thin film, and an apparatus for performing heat treatment of the thin film sheet. Tension applied to the thin film sheet is substantially equal to that applied to the base film when the magnetic thin film is formed thereon. Then, the thin film sheet is treated with heat. The thin film sheet is heated with a given temperature gradient to a reactive temperature at which heat shrinkage occurs, while the tension is being applied thereto. Thereafter, the thin film sheet to which the tension is still applied is cooled with substantially the same temperature gradient as applied in heating. The heat treatment apparatus has a film driving unit including a supply reel, a take-up reel, a drive source and guide rollers; a heating unit including heating plates, heater blocks and a temperature controller for heating the sheet to the reactive temperature; and a heat insulating unit including a thermostat and another temperature controller for maintaining the sheet at the nonreactive temperature which is slightly lower than the reactive temperature

  16. Synthesis of BaTiO3 nanoparticles from TiO2-coated BaCO3 particles derived using a wet-chemical method

    Directory of Open Access Journals (Sweden)

    Yuuki Mochizuki

    2014-03-01

    Full Text Available BaCO3 particles coated with amorphous TiO2 precursor are prepared by a wet chemical method to produce BaTiO3 nanoparticles at low temperatures. Subsequently, we investigate the formation behavior of BaTiO3 particles and the particle growth behavior when the precursor is subjected to heat treatment. The state of the amorphous TiO2 coating on the surface of BaCO3 particles depends on the concentration of NH4HCO3, and the optimum concentration is found to be in the range 0.5–1.0 M. Thermogravimetric curves of the BaCO3 particles coated with the TiO2 precursor, prepared from BaCO3 particles of various sizes, show BaTiO3 formation occurring mainly at 550–650 °C in the case of fine BaCO3 particles. However, as evidenced from the curves, the temperature of formation of BaTiO3 shifts to higher values with an increase in the size of the BaCO3 particles. The average particle size of single phase BaTiO3 at heat-treatment temperature of 650–900 °C is observed to be in the range 60–250 nm.

  17. Oxidation of ruthenium thin films using atomic oxygen

    Energy Technology Data Exchange (ETDEWEB)

    McCoy, A.P.; Bogan, J.; Brady, A.; Hughes, G.

    2015-12-31

    In this study, the use of atomic oxygen to oxidise ruthenium thin films is assessed. Atomic layer deposited (ALD) ruthenium thin films (~ 3 nm) were exposed to varying amounts of atomic oxygen and the results were compared to the impact of exposures to molecular oxygen. X-ray photoelectron spectroscopy studies reveal substantial oxidation of metallic ruthenium films to RuO{sub 2} at exposures as low as ~ 10{sup 2} L at 575 K when atomic oxygen was used. Higher exposures of molecular oxygen resulted in no metal oxidation highlighting the benefits of using atomic oxygen to form RuO{sub 2}. Additionally, the partial oxidation of these ruthenium films occurred at temperatures as low as 293 K (room temperature) in an atomic oxygen environment. - Highlights: • X-ray photoelectron spectroscopy study of the oxidation of Ru thin films • Oxidation of Ru thin films using atomic oxygen • Comparison between atomic oxygen and molecular oxygen treatments on Ru thin films • Fully oxidised RuO{sub 2} thin films formed with low exposures to atomic oxygen.

  18. Preferential growth and enhanced dielectric properties of Ba0.7Sr0.3TiO3 thin films with preannealed Pt bottom electrode

    International Nuclear Information System (INIS)

    Zhu Xiaohong; Ren Yinjuan; Zhang Caiyun; Zhu Jiliang; Zhu Jianguo; Xiao Dingquan; Defaÿ, Emmanuel; Aïd, Marc

    2013-01-01

    Ba 0.7 Sr 0.3 TiO 3 (BST) thin films, about 100 nm in thickness, were prepared on unannealed and 700 °C-preannealed Pt bottom electrodes by the ion beam sputtering and post-deposition annealing method. It was found that the preannealed Pt layer has a more compact structure, making it not only a bottom electrode but also a good template for high-quality BST thin film growth. The BST films deposited on preannealed Pt bottom electrodes showed (0 0 l)-preferred orientation, dense and uniform microstructure with no intermediate phase formed at the film/electrode interface, and thus enhanced dielectric properties. As a result, the typical relative dielectric constant and tunability (under a dc electric field of 1 MV cm −1 ) reach 180 and 50.1%, respectively, for the BST thin films with preannealed Pt bottom electrodes, which are significantly higher than those (166 and 41.3%, respectively) for the BST thin films deposited on unannealed Pt bottom electrodes. (paper)

  19. Preferential growth and enhanced dielectric properties of Ba0.7Sr0.3TiO3 thin films with preannealed Pt bottom electrode

    Science.gov (United States)

    Zhu, Xiaohong; Defaÿ, Emmanuel; Aïd, Marc; Ren, Yinjuan; Zhang, Caiyun; Zhu, Jiliang; Zhu, Jianguo; Xiao, Dingquan

    2013-03-01

    Ba0.7Sr0.3TiO3 (BST) thin films, about 100 nm in thickness, were prepared on unannealed and 700 °C-preannealed Pt bottom electrodes by the ion beam sputtering and post-deposition annealing method. It was found that the preannealed Pt layer has a more compact structure, making it not only a bottom electrode but also a good template for high-quality BST thin film growth. The BST films deposited on preannealed Pt bottom electrodes showed (0 0 l)-preferred orientation, dense and uniform microstructure with no intermediate phase formed at the film/electrode interface, and thus enhanced dielectric properties. As a result, the typical relative dielectric constant and tunability (under a dc electric field of 1 MV cm-1) reach 180 and 50.1%, respectively, for the BST thin films with preannealed Pt bottom electrodes, which are significantly higher than those (166 and 41.3%, respectively) for the BST thin films deposited on unannealed Pt bottom electrodes.

  20. Ultra-thin zirconia films on Zr-alloys

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Joong Il Jake; Mayr-Schmoelzer, Wernfried; Mittendorfer, Florian; Redinger, Josef; Diebold, Ulrike; Schmid, Michael [Institute of Applied Physics, Vienna University of Technology (Austria); Li, Hao; Rupprechter, Guenther [Institute of Materials Chemistry, Vienna University of Technology (Austria)

    2014-07-01

    Zirconia ultra-thin films have been prepared by oxidation of Pt{sub 3}Zr(0001) and showed a structure equivalent to (111) of cubic zirconia. Following previous work, we have prepared ultra-thin zirconia by oxidation of a different alloy, Pd{sub 3}Zr(0001), which resulted in a similar structure with a slightly different lattice parameter, 351.2 ±0.4 pm. Unlike the oxide on Pt{sub 3}Zr, where Zr of the oxide binds to Pt in the substrate, here the oxide binds to substrate Zr via oxygen. This causes stronger distortion of the oxide structure, i.e. a stronger buckling of Zr in the oxide. After additional oxidation of ZrO{sub 2}/Pt{sub 3}Zr, a different ultra-thin zirconia phase is observed. A preliminary structure model for this film is based on (113)-oriented cubic zirconia. 3D oxide clusters are also present after growing ultra-thin zirconia films. They occur at the step edges, and the density is higher on Pd{sub 3}Zr. These clusters also appear on terraces after additional oxidation. XPS reveals different core level shifts of the oxide films, bulk, and oxide clusters.

  1. Microstructure evolution and electrical characterization of Lanthanum doped Barium Titanate (BaTiO_3) ceramics

    International Nuclear Information System (INIS)

    Billah, Masum; Ahmed, A.; Rahman, Md. Miftaur; Mahbub, Rubbayat; Gafur, M. A.; Bashar, M. Shahriar

    2016-01-01

    In the current work, we investigated the structural and dielectric properties of Lanthanum oxide (La_2O_3) doped Barium Titanate (BaTiO_3) ceramics and established a correlation between them. Solid state sintering method was used to dope BaTiO_3 with 0.3, 0.5 and 0.7 mole% La_2O_3 under different sintering parameters. The raw materials used were La_2O_3 nano powder of ~80 nm grain size and 99.995% purity and BaTiO_3 nano powder of 100 nm grain size and 99.99% purity. Grain size distribution and morphology of fracture surface of sintered pellets were examined by Field Emission Scanning Electron Microscope and X-Ray Diffraction analysis was conducted to confirm the formation of desired crystal structure. The research result reveal that grain size and electrical properties of BaTiO_3 ceramic significantly enhanced for small amount of doping (up to 0.5 mole% La_2O_3) and then decreased with increasing doping concentration. Desired grain growth (0.80-1.3 µm) and high densification (<90% theoretical density) were found by proper combination of temperature, sintering parameters and doping concentration. We found the resultant stable value of dielectric constant was 10000-12000 at 100-300 Hz in the temperature range of 30°-50° C for 0.5 mole% La_2O_3 with corresponding shift of curie temperature around 30° C. So overall this research showed that proper La"3"+ concentration can control the grain size, increase density, lower curie temperature and hence significantly improve the electrical properties of BaTiO_3 ceramics.

  2. Bi-epitaxial YBa2Cu3Ox Thin Films on Tilted-axes NdGaO3 Substrates with CeO2 Seeding Layer

    International Nuclear Information System (INIS)

    Mozhaev, P B; Mozhaeva, J E; Jacobsen, C S; Hansen, J Bindslev; Bdikin, I K; Luzanov, V A; Kotelyanskii, I M; Zybtsev, S G

    2006-01-01

    Bi-epitaxial YBa 2 Cu 3 O x (YBCO) thin films with out-of-plane tilt angle in the range 18 - 27 0 were manufactured using pulsed laser deposition on NdGaO 3 tilted-axes substrates with CeO 2 seeding layers. The YBCO thin film orientation over the seeding layer depended on deposition conditions. Removal of the seeding layer from part of the substrate surface by ionbeam etching resulted in formation of a bi-epitaxial thin film with different c-axis orientation of two parts of the film. The bi-epitaxial film orientation and structure were studied using X-ray diffraction techniques, and surface morphology was observed with atomic force microscope (AFM). Photolithography and ion-beam etching techniques were used for patterning bi-epitaxial thin films. Electrical characterization of the obtained structures was performed

  3. Ion beam-based characterization of multicomponent oxide thin films and thin film layered structures

    International Nuclear Information System (INIS)

    Krauss, A.R.; Rangaswamy, M.; Lin, Yuping; Gruen, D.M.; Schultz, J.A.; Schmidt, H.K.; Chang, R.P.H.

    1992-01-01

    Fabrication of thin film layered structures of multi-component materials such as high temperature superconductors, ferroelectric and electro-optic materials, and alloy semiconductors, and the development of hybrid materials requires understanding of film growth and interface properties. For High Temperature Superconductors, the superconducting coherence length is extremely short (5--15 Angstrom), and fabrication of reliable devices will require control of film properties at extremely sharp interfaces; it will be necessary to verify the integrity of thin layers and layered structure devices over thicknesses comparable to the atomic layer spacing. Analytical techniques which probe the first 1--2 atomic layers are therefore necessary for in-situ characterization of relevant thin film growth processes. However, most surface-analytical techniques are sensitive to a region within 10--40 Angstrom of the surface and are physically incompatible with thin film deposition and are typically restricted to ultra high vacuum conditions. A review of ion beam-based analytical methods for the characterization of thin film and multi-layered thin film structures incorporating layers of multicomponent oxides is presented. Particular attention will be paid to the use of time-of-flight techniques based on the use of 1- 15 key ion beams which show potential for use as nondestructive, real-time, in-situ surface diagnostics for the growth of multicomponent metal and metal oxide thin films

  4. Simulation of iron impurity in BaTiO3 crystals

    International Nuclear Information System (INIS)

    Stashans, Arvids; Castillo, Darwin

    2009-01-01

    Iron-doped barium titanate (BaTiO 3 ) has been simulated taking into account cubic and tetragonal crystallographic lattices of the crystal. A quantum-chemical method based on the Hartree-Fock formalism has been used throughout the study. The calculated equilibrium structures of Fe-doped crystals reveal the defect-inward displacements of the Ti and O atoms whereas the shifts for the Ba atoms are encountered to be away with respect to the Fe impurity. According to the analysis of electron density population and electron band structure it is found that some unusual chemical bonding might take place between the Fe atom and its six adjacent O atoms. The role of Fe impurity in the ferroelectric polarization of the tetragonal BaTiO 3 crystal has been discussed too.

  5. Epitaxial growth and magnetic properties of ultraviolet transparent Ga2O3/(Ga1-xFex)2O3 multilayer thin films.

    Science.gov (United States)

    Guo, Daoyou; An, Yuehua; Cui, Wei; Zhi, Yusong; Zhao, Xiaolong; Lei, Ming; Li, Linghong; Li, Peigang; Wu, Zhenping; Tang, Weihua

    2016-04-28

    Multilayer thin films based on the ferromagnetic and ultraviolet transparent semiconductors may be interesting because their magnetic/electronic/photonic properties can be manipulated by the high energy photons. Herein, the Ga2O3/(Ga1-xFex)2O3 multilayer epitaxial thin films were obtained by alternating depositing of wide band gap Ga2O3 layer and Fe ultrathin layer due to inter diffusion between two layers at high temperature using the laser molecular beam epitaxy technique. The multilayer films exhibits a preferred growth orientation of crystal plane, and the crystal lattice expands as Fe replaces Ga site. Fe ions with a mixed valence of Fe(2+) and Fe(3+) are stratified distributed in the film and exhibit obvious agglomerated areas. The multilayer films only show a sharp absorption edge at about 250 nm, indicating a high transparency for ultraviolet light. What's more, the Ga2O3/(Ga1-xFex)2O3 multilayer epitaxial thin films also exhibits room temperature ferromagnetism deriving from the Fe doping Ga2O3.

  6. Thin Films in the Photovoltaic Industry

    International Nuclear Information System (INIS)

    Jaeger-Waldau, A.

    2008-03-01

    In the past years, the yearly world market growth rate for Photovoltaics was an average of more than 40%, which makes it one of the fastest growing industries at present. Business analysts predict the market volume to increase to 40 billion euros in 2010 and expect rising profit margins and lower prices for consumers at the same time. Today PV is still dominated by wafer based Crystalline Silicon Technology as the 'working horse' in the global market, but thin films are gaining market shares. For 2007 around 12% are expected. The current silicon shortage and high demand has kept prices higher than anticipated from the learning curve experience and has widened the windows of opportunities for thin film solar modules. Current production capacity estimates for thin films vary between 3 and 6 GW in 2010, representing a 20% market share for these technologies. Despite the higher growth rates for thin film technologies compared with the industry average, Thin Film Photovoltaic Technologies are still facing a number of challenges to maintain this growth and increase market shares. The four main topics which were discussed during the workshop were: Potential for cost reduction; Standardization; Recycling; Performance over the lifetime.

  7. Flow method for rapid production of Batio3 nanoparticles in supercritical water

    International Nuclear Information System (INIS)

    Atashfaraz, M.; Shariati-Niassar, M.; Ohara, Satoshi; Takami, S.; Umetsu, M.; Naka, T.; Adschiri, T.

    2006-01-01

    Fine BaTiO 3 nanoparticles were obtained by hydrothermal synthesis under supercritical conditions with batch and flow type experimental methods. Mixture of barium hydroxide and titanium oxide starting solution was treated in the supercritical wafer at 400 d eg C and 30 MPa. The size of nanoparticles synthesized in the flow type experiment was smaller than that in the batch type. Rapid heating in a flow, reactor is effective to synthesize smaller size and narrower particle size distribution for the BaTiO 3 , nanoparticles. The mechanism for this result was discussed based on the solubility of titanium oxide

  8. Dynamic nonlinearity in epitaxial BaTiO.sub.3./sub. films

    Czech Academy of Sciences Publication Activity Database

    Tyunina, Marina; Savinov, Maxim

    2016-01-01

    Roč. 94, č. 5 (2016), 1-6, č. článku 054109. ISSN 2469-9950 R&D Projects: GA ČR GA15-15123S Institutional support: RVO:68378271 Keywords : dynamic nonlinearity * epitaxial * BaTiO 3 films Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.836, year: 2016

  9. Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells

    OpenAIRE

    Wang Lan; Lin Xianzhong; Ennaoui Ahmed; Wolf Christian; Lux-Steiner Martha Ch.; Klenk Reiner

    2016-01-01

    We report a route to deposit In2S3 thin films from air-stable, low-cost molecular precursor inks for Cd-free buffer layers in chalcopyrite-based thin film solar cells. Different precursor compositions and processing conditions were studied to define a reproducible and robust process. By adjusting the ink properties, this method can be applied in different printing and coating techniques. Here we report on two techniques, namely spin-coating ...

  10. Lattice distortion under an electric field in BaTiO3 piezoelectric single crystal

    International Nuclear Information System (INIS)

    Tazaki, Ryoko; Fu Desheng; Daimon, Masahiro; Koshihara, Shin-ya; Itoh, Mitsuru

    2009-01-01

    Lattice distortions under an electric field in a mono-domain of BaTiO 3 ferroelectric crystal have been detected with synchrotron x-ray radiation. The variation of the lattice constant with an electric field observed with high angle diffraction shows a linear response nature of the piezoelectric effect. When an electric field is applied along the spontaneous polarization direction, the c-axis of the lattice elongates and the a-axis of the lattice shrinks at a rate of d 33 = 149 ± 54 pm V -1 and d 31 = -82 ± 61 pm V -1 ; these represent the longitudinal and transverse piezoelectric coefficients of BaTiO 3 crystal, respectively. These results give an insight into the intrinsic piezoelectric response on the lattice scale in BaTiO 3 that has been widely used to explore high performance lead-free piezoelectric alloys.

  11. Magnetoresistance Versus Oxygen Deficiency in Epi-stabilized SrRu1 - x Fe x O3 - δ Thin Films

    Science.gov (United States)

    Dash, Umasankar; Acharya, Susant Kumar; Lee, Bo Wha; Jung, Chang Uk

    2017-03-01

    Oxygen vacancies have a profound effect on the magnetic, electronic, and transport properties of transition metal oxide materials. Here, we studied the influence of oxygen vacancies on the magnetoresistance (MR) properties of SrRu1 - x Fe x O3 - δ epitaxial thin films ( x = 0.10, 0.20, and 0.30). For this purpose, we synthesized highly strained epitaxial SrRu1 - x Fe x O3 - δ thin films with atomically flat surfaces containing different amounts of oxygen vacancies using pulsed laser deposition. Without an applied magnetic field, the films with x = 0.10 and 0.20 showed a metal-insulator transition, while the x = 0.30 thin film showed insulating behavior over the entire temperature range of 2-300 K. Both Fe doping and the concentration of oxygen vacancies had large effects on the negative MR contributions. For the low Fe doping case of x = 0.10, in which both films exhibited metallic behavior, MR was more prominent in the film with fewer oxygen vacancies or equivalently a more metallic film. For semiconducting films, higher MR was observed for more semiconducting films having more oxygen vacancies. A relatively large negative MR ( 36.4%) was observed for the x = 0.30 thin film with a high concentration of oxygen vacancies ( δ = 0.12). The obtained results were compared with MR studies for a polycrystal of (Sr1 - x La x )(Ru1 - x Fe x )O3. These results highlight the crucial role of oxygen stoichiometry in determining the magneto-transport properties in SrRu1 - x Fe x O3 - δ thin films.

  12. Study on epoxy/BaTiO3 composite embedded capacitor films (ECFs) for organic substrate applications

    International Nuclear Information System (INIS)

    Cho, Sung-Dong; Lee, Joo-Yeon; Hyun, Jin-Gul; Paik, Kyung-Wook

    2004-01-01

    Embedded capacitor films (ECFs) were newly designed for high dielectric constant and low capacitance tolerance (less than ±5%) embedded capacitor fabrication for organic substrates. ECFs are transferable and B-stage films which can be coated on a releasing film. In terms of materials formulation, ECFs are composed of high dielectric constant BaTiO 3 (BT) powder, specially formulated epoxy resin, and latent curing agent. And in terms of coating process, a roll coating method is used for obtaining film thickness uniformity in a large area. Differential scanning calorimeter (DSC) thermal analysis was conducted to determine the optimum amount of curing agent, curing temperature, and curing time. Changes in the dielectric constant of epoxy/BaTiO 3 composite ECFs with BT particle sizes and contents were investigated. Dielectric constant of 90 was obtained using two different size BaTiO 3 powders mixture. Typically, capacitors of 12 μm thick film with 8 nF/cm 2 with less than ±5% capacitance tolerance and low leakage current (less than 10 -7 A/cm 2 at 10 V) were successfully demonstrated on PCBs using epoxy/BaTiO 3 composite embedded capacitor films

  13. Impact of symmetry on the ferroelectric properties of CaTiO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Biegalski, Michael D.; Qiao, Liang [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Gu, Yijia; Chen, Long-Qing [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16801 (United States); Mehta, Apurva [Stanford Synchrotron Lightsource SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); He, Qian; Borisevich, Albina [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Takamura, Yayoi, E-mail: ytakamura@ucdavis.edu [Department of Chemical Engineering and Materials Science, University of California Davis, Davis, California 95616 (United States)

    2015-04-20

    Epitaxial strain is a powerful tool to induce functional properties such as ferroelectricity in thin films of materials that do not possess ferroelectricity in bulk form. In this work, a ferroelectric state was stabilized in thin films of the incipient ferroelectric, CaTiO{sub 3}, through the careful control of the biaxial strain state and TiO{sub 6} octahedral rotations. Detailed structural characterization was carried out by synchrotron x-ray diffraction and scanning transmission electron microscopy. CaTiO{sub 3} films grown on La{sub 0.18}Sr{sub 0.82}Al{sub 0.59}Ta{sub 0.41}O{sub 3} (LSAT) and NdGaO{sub 3} (NGO) substrates experienced a 1.1% biaxial strain state but differed in their octahedral tilt structures. A suppression of the out-of-plane rotations of the TiO{sub 6} octahedral in films grown on LSAT substrates resulted in a robust ferroelectric I4 mm phase with remnant polarization ∼5 μC/cm{sup 2} at 10 K and T{sub c} near 140 K. In contrast, films grown on NGO substrates with significant octahedral tilting showed reduced polarization and T{sub c}. These results highlight the key role played by symmetry in controlling the ferroelectric properties of perovskite oxide thin films.

  14. Silicon-integrated thin-film structure for electro-optic applications

    Science.gov (United States)

    McKee, Rodney A.; Walker, Frederick Joseph

    2000-01-01

    A crystalline thin-film structure suited for use in any of an number of electro-optic applications, such as a phase modulator or a component of an interferometer, includes a semiconductor substrate of silicon and a ferroelectric, optically-clear thin film of the perovskite BaTiO.sub.3 overlying the surface of the silicon substrate. The BaTiO.sub.3 thin film is characterized in that substantially all of the dipole moments associated with the ferroelectric film are arranged substantially parallel to the surface of the substrate to enhance the electro-optic qualities of the film.

  15. Catalytic EC′ reaction at a thin film modified electrode

    International Nuclear Information System (INIS)

    Gerbino, Leandro; Baruzzi, Ana M.; Iglesias, Rodrigo A.

    2013-01-01

    Numerical simulations of cyclic voltammograms corresponding to a catalytic EC′ reaction taking place at a thin film modified electrode are performed by way of finite difference method. Besides considering the chemical kinetic occurring inside the thin film, the model takes into account the different diffusion coefficients for each species at each of the involved phases, i.e. the thin film layer and bulk solution. The theoretical formulation is given in terms of dimensionless model parameters but a brief discussion of each of these parameters and their relationship to experimental variables is presented. Special emphasis is given to the use of working curve characteristics to quantify diffusion coefficient, homogeneous kinetic constant and thickness of the thin layer in a real system. Validation of the model is made by comparison of experimental results corresponding to the electron charge transfer of Ru(NH 3 ) 6 3+ /Ru(NH 3 ) 6 2+ hemi-couple at a thin film of a cross-linked chitosan film containing an immobilized redox dye

  16. Nanometric thin film membranes manufactured on square meter scale: ultra-thin films for CO 2 capture

    KAUST Repository

    Yave, Wilfredo

    2010-09-01

    Miniaturization and manipulation of materials at nanometer scale are key challenges in nanoscience and nanotechnology. In membrane science and technology, the fabrication of ultra-thin polymer films (defect-free) on square meter scale with uniform thickness (<100 nm) is crucial. By using a tailor-made polymer and by controlling the nanofabrication conditions, we developed and manufactured defect-free ultra-thin film membranes with unmatched carbon dioxide permeances, i.e. >5 m3 (STP) m-2 h -1 bar-1. The permeances are extremely high, because the membranes are made from a CO2 philic polymer material and they are only a few tens of nanometers thin. Thus, these thin film membranes have potential application in the treatment of large gas streams under low pressure like, e.g., carbon dioxide separation from flue gas. © 2010 IOP Publishing Ltd.

  17. Microstructure of epitaxial SrRuO 3 thin films on MgO substrates

    Science.gov (United States)

    Ai, Wan Yong; Zhu, Jun; Zhang, Ying; Li, Yan Rong; Liu, Xing Zhao; Wei, Xian Hua; Li, Jin Long; Zheng, Liang; Qin, Wen Feng; Liang, Zhu

    2006-09-01

    SrRuO 3 thin films have been grown on singular (1 0 0) MgO substrates using pulsed laser deposition (PLD) in 30 Pa oxygen ambient and at a temperature of 400-700 °C. Ex situ reflection high-energy electron diffraction (RHEED) as well as X-ray diffraction (XRD) θ/2 θ scan indicated that the films deposited above 650 °C were well crystallized though they had a rough surface as shown by atom force microscopy (AFM). XRD Φ scans revealed that these films were composed of all three different types of orientation domains, which was further confirmed by the RHEED patterns. The heteroepitaxial relationship between SrRuO 3 and MgO was found to be [1 1 0] SRO//[1 0 0] MgO and 45°-rotated cube-on-cube [0 0 1] SRO//[1 0 0] MgO. These domain structures and surface morphology are similar to that of ever-reported SrRuO 3 thin films deposited on the (0 0 1) LaAlO 3 substrates, and different from those deposited on (0 0 1) SrTiO 3 substrates that have an atomically flat surface and are composed of only the [1 1 0]-type domains. The reason for this difference was ascribed to the effect of lattice mismatch across the film/substrate interface. The room temperature resistivity of SrRuO 3 films fabricated at 700 °C was 300 μΩ cm. Therefore, epitaxial SrRuO 3 films on MgO substrate could serve as a promising candidate of electrode materials for the fabrication of ferroelectric or dielectric films.

  18. Optical response of Cu3Ge thin films

    OpenAIRE

    Aboelfotoh, M. O.; Guizzetti, G.; Marabelli, F.; Pellegrino, Paolo; Sassella, A.

    1996-01-01

    We report an investigation on the optical properties of Cu3Ge thin films displaying very high conductivity, with thickness ranging from 200 to 2000 Å, deposited on Ge substrates. Reflectance, transmittance, and ellipsometric spectroscopy measurements were performed at room temperature in the 0.01-6.0, 0.01-0.6, and 1.4-5.0 eV energy range, respectively. The complex dielectric function, the optical conductivity, the energy-loss function, and the effective charge density were obtained over the ...

  19. Structure and electrical properties of Pb(ZrxTi1-x)O3 deposited on textured Pt thin films

    International Nuclear Information System (INIS)

    Hong, Jongin; Song, Han Wook; Lee, Hee Chul; Lee, Won Jong; No, Kwangsoo

    2001-01-01

    The texturing of the bottom electrode plays a key role in the structure and electrical properties of Pb(Zr,Ti)O 3 (PZT) thin films. We fabricated Pt bottom electrodes having a different thickness on MgO single crystals at 600 o C by rf magnetron sputtering. As the thickness of platinum (Pt) thin film increased, the preferred orientation of Pt thin film changed from (200) to (111). PZT thin films were fabricated at 450 o C by electron cyclotron resonance-plasma enhanced metal organic chemical vapor deposition on the textured Pt thin films. The texturing of the bottom electrode caused drastic changes in the C--V characteristics, P--E characteristics, and fatigue characteristics of metal/ferroelectric material/metal (MFM) capacitors. The difference of the electrical properties between the PZT thin films having different texturing was discussed in terms-of the x--y alignment and the interface between electrode and PZT in MFM capacitors. copyright 2001 American Institute of Physics

  20. Processing and properties of Pb(Mg(1/3)Nb(2/3))O3--PbTiO3 thin films by pulsed laser deposition

    Science.gov (United States)

    Tantigate, C.; Lee, J.; Safari, A.

    1995-03-01

    The objectives of this study were to prepare in situ Pb(Mg(1/3)Nb(2/3))O3 (PMN) and PMN-PT thin films by pulsed laser deposition and to investigate the electrical features of thin films for possible dynamic random access memory (DRAM) and microactuator applications. The impact of processing parameters such compositions, substrate temperature, and oxygen pressure on perovskite phase formation and dielectric characteristics were reported. It was found that the highest dielectric constant, measured at room temperature and 10 kHz, was attained from the PMN with 99% perovskite.

  1. Metalorganic chemical vapor deposition of Er{sub 2}O{sub 3} thin films: Correlation between growth process and film properties

    Energy Technology Data Exchange (ETDEWEB)

    Giangregorio, Maria M. [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR and INSTM sez. Bari, Via Orabona 4, 70125 Bari (Italy)], E-mail: michelaria.giangregorio@ba.imip.cnr.it; Losurdo, Maria; Sacchetti, Alberto; Capezzuto, Pio; Bruno, Giovanni [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR and INSTM sez. Bari, Via Orabona 4, 70125 Bari (Italy)

    2009-02-27

    Er{sub 2}O{sub 3} thin films have been grown by metalorganic chemical vapor deposition (MOCVD) at 600 deg. C on different substrates, including glass, Si (100) and sapphire (0001) using tris(isopropylcyclopentadienyl)erbium and O{sub 2}. The effects of growth parameters such as the substrate, the O{sub 2} plasma activation and the temperature of organometallic precursor injection, on the nucleation/growth kinetics and, consequently, on film properties have been investigated. Specifically, very smooth (111)-oriented Er{sub 2}O{sub 3} thin films (the root mean square roughness is 0.3 nm) are achieved on Si (100), {alpha}-Al{sub 2}O{sub 3} (0001) and amorphous glass by MOCVD. Growth under O{sub 2} remote plasma activation results in an increase in growth rate and in (100)-oriented Er{sub 2}O{sub 3} films with high refractive index and transparency in the visible photon energy range.

  2. Physical properties of chemically deposited Bi{sub 2}S{sub 3} thin films using two post-deposition treatments

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-García, H., E-mail: hamog@ier.unam.mx [Instituto de Ciencias Físicas, Laboratorio de espectroscopia, Universidad Nacional Autónoma de México, Apartado Postal 48-3, C.P. 62210 Cuernavaca, Morelos (Mexico); Messina, S. [Universidad Autónoma de Nayarit, Ciudad de la Cultura “Amado Nervo” S/N, C.P. 63155 Tepic, Nayarit (Mexico); Calixto-Rodriguez, M. [Universidad Tecnológica Emiliano Zapata del Estado de Morelos, Av. Universidad Tecnológica No. 1, C.P. 62760 Emiliano Zapata, Morelos (Mexico); Martínez, H. [Instituto de Ciencias Físicas, Laboratorio de espectroscopia, Universidad Nacional Autónoma de México, Apartado Postal 48-3, C.P. 62210 Cuernavaca, Morelos (Mexico)

    2014-08-30

    Highlights: • The post-deposition treatment by Ar plasma is a viable alternative to enhance the optical, electrical, morphological and structural properties of Bi{sub 2}S{sub 3} semiconductor thin films. • The plasma treatment avoids the loss in thickness of the chemically deposited Bi{sub 2}S{sub 3} thin films. • The E{sub g} values were 1.60 eV for the thermally annealed samples and 1.56 eV for the Ar plasma treated samples. • The highest value obtained for the electrical conductivity was 7.7 × 10{sup −2} (Ω cm){sup −1} in plasma treated samples. - Abstract: As-deposited bismuth sulfide (Bi{sub 2}S{sub 3}) thin films prepared by chemical bath deposition technique were treated with thermal annealed in air atmosphere and argon AC plasma. The as-deposited, thermally annealing and plasma treatment Bi{sub 2}S{sub 3} thin films have been characterized by X-ray diffraction (XRD) analysis, atomic force microscopy analysis (AFM), transmission, specular reflectance and electrical measurements. The structural, morphological, optical and electrical properties of the films are compared. The XRD analysis showed that both post-deposition treatments, transform the thin films from amorphous to a crystalline phase. The atomic force microscopy (AFM) measurement showed a reduction of roughness for the films treated in plasma. The energy band gap value of the as-prepared film was E{sub g} = 1.61 eV, while for the film thermally annealed was E{sub g} = 1.60 eV and E{sub g} = 1.56 eV for film treated with Plasma. The electrical conductivity under illumination of the as-prepared films was 3.6 × 10{sup −5} (Ω cm){sup −1}, whereas the conductivity value for the thermally annealed films was 2.0 × 10{sup −3} (Ω cm){sup −1} and for the plasma treated films the electrical conductivity increases up to 7.7 × 10{sup −2} (Ω cm){sup −1}.

  3. Characterization, dielectric and electrical behaviour of BaTiO3 ...

    Indian Academy of Sciences (India)

    Administrator

    of λ = 0⋅1542 nm, for crystal structure determination. Scherrer's equation and ... ion, releasing one molecule of propanol and one molecule of triethanolamine in .... The OH, CO2 and CO3 peaks were reduced in the sam- ple of BaTiO3 when ...

  4. Oxygen tracer studies of ferroelectric fatigue in Pb(Zr,Ti)O3 thin films

    International Nuclear Information System (INIS)

    Schloss, Lawrence F.; McIntyre, Paul C.; Hendrix, Bryan C.; Bilodeau, Steven M.; Roeder, Jeffrey F.; Gilbert, Stephen R.

    2002-01-01

    Long-range oxygen motion has been observed in Pt/Pb(Zr,Ti)O 3 /Ir thin-film structures after electrical fatigue cycling at room temperature. Through an exchange anneal, isotopic 18 O was incorporated as a tracer into bare Pb(Zr,Ti)O 3 (PZT) films, allowing secondary ion mass spectrometry measurements of the tracer profile evolution as a function of the number of polarization reversals. Observation of 18 O tracer redistribution during voltage cycling, which is presumably mediated by oxygen vacancy motion, was found to be strongly dependent upon the thermal history of the film. However, there was no strong correlation between the extent of 18 O tracer redistribution and the extent of polarization suppression induced by voltage cycling. Our results suggest that oxygen vacancy motion plays, at most, a secondary role in ferroelectric fatigue of PZT thin films

  5. Growth of amorphous TeOx (2≤x≤3) thin film by radio frequency sputtering

    International Nuclear Information System (INIS)

    Dewan, Namrata; Gupta, Vinay; Sreenivas, K.; Katiyar, R. S.

    2007-01-01

    Thin films of Tellurium oxide TeO x over a wide range of x (2 to 3) were prepared by radio frequency diode sputtering at room temperature on corning glass and quartz substrate. The deposited films are amorphous in nature and IR spectroscopy reveals the formation of Te-O bond. X-ray photoelectron spectroscopy shows the variation in the stoichiometry of TeO x film from x=2 to 3 with an increase in oxygen percentage (25 to 100%) in processing sputtering gas composition. Raman spectroscopy depicts the formation of TeO 3 trigonal pyramid besides TeO 4 disphenoid in the amorphous TeO x film with increase in the value of x. The varying stoichiometry of TeO x thin film (x=2 to 3) was found to influence the optical, electrical, and elastic properties. The optical band gap of film increases from 3.8 to 4.2 eV with increasing x and is attributed to the decrease in density. The elastic constants (C 11 and C 44 ) of the deposited films are lower than the corresponding value reported for TeO 2 single crystal

  6. Gasochromic performance of WO{sub 3}-nanorod thin films fabricated with an ArF excimer laser

    Energy Technology Data Exchange (ETDEWEB)

    Yaacob, M. H. [RMIT University, Melbourne (Australia); Universiti Putra Malaysia, Selangor (Malaysia); Ou, J. Z.; Wlodarski, W. [RMIT University, Melbourne (Australia); Kim, C. S.; Lee, J. Y. [KAIST, Daejon (Korea, Republic of); Kim, Y. H. [KIST, Seoul (Korea, Republic of); Oh, C. M.; Dhakal, K. P.; Kim, J. Y.; Kang, J. H. [University of Incheon, Incheon (Korea, Republic of)

    2012-02-15

    Thin films with tungsten trioxide (WO{sub 3}) nanorods were fabricated by using an ArF pulsed laser deposition system. Because the ArF excimer laser operates at a very short wavelength of 193 nm, short enough to expect strong absorption of the photons in the semiconductor oxide targets, and because the clusters incoming to the substrates have high momentum, we could build thin films with good surface morphology. Highly homogeneous arrays of nanorods with sizes mostly in the range of 30 - 40 nm were observed. The absorbance response towards hydrogen (H{sub 2}) gas was investigated for a WO{sub 3} film coated with 25-A-thick palladium (Pd). The Pd/WO{sub 3}-nanorod thin films exhibited excellent gasochromic response when measured in the visible-NIR range (400 - 1000 nm). As low as 0.06% H{sub 2} concentration was clearly sensed. A significant reversible absorbance change and fast recovery (<2 min) were observed when the films were exposed to H{sub 2} at different concentrations.

  7. P-type CuxS thin films: Integration in a thin film transistor structure

    International Nuclear Information System (INIS)

    Nunes de Carvalho, C.; Parreira, P.; Lavareda, G.; Brogueira, P.; Amaral, A.

    2013-01-01

    Cu x S thin films, 80 nm thick, are deposited by vacuum thermal evaporation of sulfur-rich powder mixture, Cu 2 S:S (50:50 wt.%) with no intentional heating of the substrate. The process of deposition occurs at very low deposition rates (0.1–0.3 nm/s) to avoid the formation of Cu or S-rich films. The evolution of Cu x S films surface properties (morphology/roughness) under post deposition mild annealing in air at 270 °C and their integration in a thin film transistor (TFT) are the main objectives of this study. Accordingly, Scanning Electron Microscopy studies show Cu x S films with different surface morphologies, depending on the post deposition annealing conditions. For the shortest annealing time, the Cu x S films look to be constructed of grains with large dimension at the surface (approximately 100 nm) and consequently, irregular shape. For the longest annealing time, films with a fine-grained surface are found, with some randomly distributed large particles bound to this fine-grained surface. Atomic Force Microscopy results indicate an increase of the root-mean-square roughness of Cu x S surface with annealing time, from 13.6 up to 37.4 nm, for 255 and 345 s, respectively. The preliminary integration of Cu x S films in a TFT bottom-gate type structure allowed the study of the feasibility and compatibility of this material with the remaining stages of a TFT fabrication as well as the determination of the p-type characteristic of the Cu x S material. - Highlights: • Surface properties of annealed Cu x S films. • Variation of conductivity with annealing temperatures of Cu x S films. • Application of evaporated Cu x S films in a thin film transistor (TFT) structure. • Determination of Cu x S p-type characteristic from TFT behaviour

  8. Síntesis de polvos de BaTiO3 por mecanoquímica

    Directory of Open Access Journals (Sweden)

    Villaquirán Raigoza, C. F.

    2002-02-01

    Full Text Available The barium titanato, BaTiO3, is one of the electronic ceramics with more history of technological application in the industry of the ceramic capacitores. The actual technological demands, and the high quality required for the electronic devices, have driven to new alternatives of prosecution of these materials and to optimize the traditional techniques of raw materials synthesis it prevails. An alternative synthesis is to use the mechanical energy to modify the physiochemical properties of the dispersed system and to favor the obtaining of powders of BaTiO3. In this work the results are indicated obtained when using mechanical activation, physicochemistry, in the obtaining of the BaTiO3. It has been analyzed the effect of the time of mill and the nature of the precursor of the titanium on the transformation of phases in the samples during the thermal treatment to that are subjected. X-ray diffraction, DRX, was used to study the phases evolution and infrared spectroscopy, FTIR, to determine the functional groups present in the samples.El titanato de bario, BaTiO3, es uno de los cerámicos electrónicos con mayor historia de aplicación tecnológica en la industria de los capacitores cerámicos. Las demandas tecnológicas actuales, y la alta calidad requerida para los dispositivos electrónicos, han conducido a nuevas alternativas de procesamiento de estos materiales y a optimizar las técnicas tradicionales de síntesis de materia prima. Una alternativa de síntesis es utilizar la energía mecánica para modificar las propiedades fisicoquímicas del sistema disperso y favorecer la obtención de polvos de BaTiO3. En este trabajo se indican los resultados obtenidos al utilizar activación mecánica, mecanoquímica, en la obtención del BaTiO3. Se ha analizado el efecto del tiempo de molienda y la naturaleza del precursor del titanio sobre la transformación de fases que experimentan las muestras durante el tratamiento térmico a que son sometidas

  9. Pulsed Laser deposition of Al2O3 thin film on silicon

    International Nuclear Information System (INIS)

    Lamagna, A.; Duhalde, S.; Correra, L.; Nicoletti, S.

    1998-01-01

    Al 2 O 3 thin films were fabricated by pulsed laser deposition (PLD) on Si 3 N 4 /Si, to improve the thermal and electrical isolation of gas sensing devices. The microstructure of the films is analysed as a function of the deposition conditions (laser fluence, oxygen pressure, target-substrate distance and substrate temperature). X-ray analysis shows that only a sharp peak that coincides with the corundum (116) reflection can be observed in all the films. But, when they are annealed at temperatures above 1,200 degree centigrade, a change in the crystalline structure of some films occurs. The stoichiometry and morphology of the films with and without thermal treatment are compared using environmental scanning electron microscopy (SEM) and EDAX analysis. (Author) 14 refs

  10. Mechanism of Crystallization and Implications for Charge Transport in Poly(3-ethylhexylthiophene) Thin Films

    KAUST Repository

    Duong, Duc T.; Ho, Victor; Shang, Zhengrong; Mollinger, Sonya; Mannsfeld, Stefan C.B.; Dacuñ a, Javier; Toney, Michael F.; Segalman, Rachel; Salleo, Alberto

    2014-01-01

    on the film thickness and average molecular weight. Time-dependent, field-effect hole mobilities in thin films reveal a percolation threshold for both low and high molecular weight P3EHT. Structural analysis reveals that charge percolation requires bridged

  11. Persistent semi-metal-like nature of epitaxial perovskite CaIrO3 thin films

    International Nuclear Information System (INIS)

    Biswas, Abhijit; Jeong, Yoon Hee

    2015-01-01

    Strong spin-orbit coupled 5d transition metal based ABO 3 oxides, especially iridates, allow tuning parameters in the phase diagram and may demonstrate important functionalities, for example, by means of strain effects and symmetry-breaking, because of the interplay between the Coulomb interactions and strong spin-orbit coupling. Here, we have epitaxially stabilized high quality thin films of perovskite (Pv) CaIrO 3 . Film on the best lattice-matched substrate shows semi-metal-like characteristics. Intriguingly, imposing tensile or compressive strain on the film by altering the underlying lattice-mismatched substrates still maintains semi-metallicity with minute modification of the effective correlation as tensile (compressive) strain results in tiny increases (decreases) of the electronic bandwidth. In addition, magnetoresistance remains positive with a quadratic field dependence. This persistent semi-metal-like nature of Pv-CaIrO 3 thin films with minute changes in the effective correlation by strain may provide new wisdom into strong spin-orbit coupled 5d based oxide physics

  12. Chemical solution deposition of CaCu 3 Ti 4 O 12 thin film

    Indian Academy of Sciences (India)

    CaCu3Ti4O12 (CCTO) thin film was successfully deposited on boron doped silica substrate by chemical solution deposition and rapid thermal processing. The phase and microstructure of the deposited films were studied as a function of sintering temperature, employing X-ray diffractometry and scanning electron ...

  13. Highly polarized single-c-domain single-crystal Pb(Mn,Nb)O(3)-PZT thin films.

    Science.gov (United States)

    Wasa, Kiyotaka; Adachi, Hideaki; Nishida, Ken; Yamamoto, Takashi; Matsushima, Tomoaki; Kanno, Isaku; Kotera, Hidetoshi

    2012-01-01

    In-plane unstrained single-c-domain/single-crystal thin films of PZT-based ternary ferroelectric perovskite, ξPb(Mn,Nb)O3-(1 - ξ)PZT, were grown on SrRuO(3)/Pt/MgO substrates using magnetron sputtering followed by quenching. The sputtered unstrained thin films exhibit unique ferroelectric properties: high coercive field, Ec > 180 kV/cm, large remanent polarization, P(r) = 100 μC/cm(2), small relative dielectric constants, ε* = 100 to 150, high Curie temperature, Tc = ~600 °C, and bulk-like large transverse piezoelectric constants, e31,f = -12.0 C/m(2) for PZT(48/52) at ξ = 0.06. The unstrained thin films are an ideal structure to extract the bulk ferroelectric properties. Their micro-structures and ferroelectric properties are discussed in relation to the potential applications for piezoelectric MEMS. © 2012 IEEE

  14. Microwave-Hydrothermal Synthesis and Characterization of High-Purity Nb Doped BaTiO3 Nanocrystals

    Directory of Open Access Journals (Sweden)

    A. Khanfekr

    2014-01-01

    Full Text Available The synthesis of Nb doped BaTiO3 has been investigated under Microwave-Hydrothermal (MH conditions in the temperature of 150°C for only 2 h using C16H36O4Ti, BaH2O2.8H2O and NbCl5 as Ba, Ti and  Nb sources, respectively.  Typical experiments performed on MH processing have not yet reported for Nb doped BaTiO3.  In the MH process, the formation of high purity nano tetragonal Nb-BaTiO3 was strongly enhanced. New hydrothermal method was used instead of the previous solid state reaction for the BaTiO3±Nb2O3 system. The new method uses high pressure to create nano dimension particles in a lower time and temperature. In case of the phase evolution studies, the XRD pattern measurements and Raman spectroscopy were performed. TEM and FE-SEM images were taken for the detailed analysis of the particle size, surface and morphology.  Synthesis of Nb doped BaTiO3 with the Microwave-hydrothermal provides an advantage of fast crystallization and reduced crystal size when compared to existing methods.

  15. Direct Observation of Surface Potential Distribution in Insulation Resistance Degraded Acceptor-Doped BaTiO3 Multilayered Ceramic Capacitors

    Science.gov (United States)

    Hong, Kootak; Lee, Tae Hyung; Suh, Jun Min; Park, Jae-Sung; Kwon, Hyung-Soon; Choi, Jaeho; Jang, Ho Won

    2018-05-01

    Insulation resistance (IR) degradation in BaTiO3 is a key issue for developing miniaturized multilayer ceramic capacitors (MLCCs) with high capacity. Despite rapid progress in BaTiO3-based MLCCs, the mechanism of IR degradation is still controversial. In this study, we demonstrate the Al doping effect on IR degradation behavior of BaTiO3 MLCCs by electrical measurements and scanning Kelvin probe microscopy (SKPM). As the Al doping concentration in BaTiO3 increases, IR degradation of MLCCs seems to be suppressed from electrical characterization results. However, SKPM results reveal that the conductive regions near the cathode become lager with Al doping after IR degradation. The formation of conducting regions is attributed to the migration of oxygen vacancies, which is the origin of IR degradation in BaTiO3, in dielectric layers. These results imply that acceptor doping in BaTiO3 solely cannot suppress the IR degradation in MLCC even though less asymmetric IR characteristics and IR degradation in MLCCs with higher Al doping concentration are observed from electrical characterization. Our results strongly suggest that observing the surface potential distribution in IR degraded dielectric layers using SKPM is an effective method to unravel the mechanism of IR degradation in MLCCs.

  16. DC magnetron sputtering prepared Ag-C thin film anode for thin film lithium ion microbatteries

    International Nuclear Information System (INIS)

    Li, Y.; Tu, J.P.; Shi, D.Q.; Huang, X.H.; Wu, H.M.; Yuan, Y.F.; Zhao, X.B.

    2007-01-01

    An Ag-C thin film was prepared by DC magnetron co-sputtering, using pure silver and graphite as the targets. The microstructure and morphology of the deposited thin film were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Electrochemical performances of the Ag-C thin film anode were investigated by means of discharge/charge and cyclic voltammogram (CV) tests in model cells. The electrochemical impedance spectrum (EIS) characteristics and the chemical diffusion coefficient, D Li of the Ag-C thin film electrode at different discharging states were discussed. It was believed that the excellent cycling performance of the Ag-C electrode was ascribed to the good conductivity of silver and the volume stability of the thin film

  17. Preparation of planar CH3NH3PbI3 thin films with controlled size using 1-ethyl-2-pyrrolidone as solvent

    International Nuclear Information System (INIS)

    Hao, Qiuyan; Chu, Yixia; Zheng, Xuerong; Liu, Zhenya; Liang, Liming; Qi, Jiakun; Zhang, Xin; Liu, Gang; Liu, Hui; Chen, Hongjian; Liu, Caichi

    2016-01-01

    Recently, planar perovskite solar cells based on CH 3 NH 3 PbI 3 have attracted many researcher's interest due to their unique advantages such as simple cell architecture, easy fabrication and potential multijunction construction comparing to the initial mesoporous structure. However, the preparation of planar perovskite films with high quality is still in challenge. In this paper, we developed a vapor-assisted solution process using a novel and green solvent of 1-Ethyl-2-pyrrolidone (NEP) instead of the traditional N, N-dimethylformamide (DMF) to construct a high-quality perovskite CH 3 NH 3 PbI 3 thin film with pure phase, high compactness, small surface roughness and controlled size. The phase evolution and growth mechanism of the perovskite films are also discussed. Utilizing the NEP of low volatility and moderate boiling point as solvent, we dried the PbI 2 -NEP precursor films at different temperature under vacuum and then obtained PbI 2 thin films with different crystalline degree from amorphous to highly crystalline. The perovskite films with crystal size ranged from hundreds of nanometers to several micrometers can be prepared by reacting the PbI 2 films of different crystalline degree with CH 3 NH 3 I vapor. Moreover, planar-structured solar cells combining the perovskite film with TiO 2 and spiro-OMeTAD as the electron and holes transporting layer achieves a power conversion efficiency of 10.2%. - Highlights: • A novel and green solvent of 1-Ethyl-2-pyrrolidone (NEP) was used to construct high-quality perovskite CH 3 NH 3 PbI 3 thin film. • The CH 3 NH 3 PbI 3 grain with different sizes ranged from hundreds of nanometers to several micrometers can be obtained. • Planar-structured perovskite CH 3 NH 3 PbI 3 solar cells using NEP as solvent achieves a power conversion efficiency of 10.2%.

  18. Electrical transport properties of MoO3 thin films prepared by laser assisted evaporation

    International Nuclear Information System (INIS)

    Lopez-Carreno, L.D.; Pardo, A.; Zuluaga, M.; Torres, J.; Alfonso, J.E.; Cortes-Bracho, O.L.

    2007-01-01

    In the present paper the growth of MoO 3 thin films on common glass substrates are described. The films were prepared by evaporation of a MoO 3 target with a CO 2 laser (10.6 μm), operating in the continuous wave mode. The effect of substrate temperature on the crystallographic structure and electrical properties of MoO 3 thin films was studied. The chemical composition of the different species formed on the films surface was obtained by X-ray photoelectron spectroscopy (XPS) and the crystalline structure was studied with X-ray diffraction (XRD). The electrical conductivity of the films was determined using the standard four-points method. Conductivity of the films varied from de 10 -9 to 10 -5 (Ωcm) -1 in the 300-600 K temperature range. Arrhenius-type plots for the electrical conductivity indicate the presence of at least two different conduction mechanisms. The I-V characteristic curve shows an ohmic behavior only in the 4.5-60 V range. Outside this interval the I-V curve has a behavior described by a power law. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Temperature studies of optical parameters of (Ag3AsS3)0.6(As2S3)0.4 thin films prepared by rapid thermal evaporation and pulse laser deposition

    Science.gov (United States)

    Studenyak, I. P.; Kutsyk, M. M.; Buchuk, M. Yu.; Rati, Y. Y.; Neimet, Yu. Yu.; Izai, V. Yu.; Kökényesi, S.; Nemec, P.

    2016-02-01

    (Ag3AsS3)0.6(As2S3)0.4 thin films were deposited using rapid thermal evaporation (RTE) and pulse laser deposition (PLD) techniques. Ag-enriched micrometre-sized cones (RTE) and bubbles (PLD) were observed on the thin film surface. Optical transmission spectra of the thin films were studied in the temperature range 77-300 K. The Urbach behaviour of the optical absorption edge in the thin films due to strong electron-phonon interaction was observed, the main parameters of the Urbach absorption edge were determined. Temperature dependences of the energy position of the exponential absorption edge and the Urbach energy are well described in the Einstein model. Dispersion and temperature dependences of refractive indices were analysed; a non-linear increase of the refractive indices with temperature was revealed. Disordering processes in the thin films were studied and compared with bulk composites, the differences between the thin films prepared by RTE and PLD were analysed.

  20. Modeling flux pinning in thin undoped and BazRo3-doped YBCO films

    DEFF Research Database (Denmark)

    Paturi, P.; Irjala, M.; Huhtinen, H.

    2009-01-01

    A simple model based on distributions of twin boundaries, dislocations, and BaZrO3 nanorods is presented to describe the Jc properties of undoped and BaZrO3 (BZO)-doped YBa2Cu3Ox thin films. The model accurately describes the shape of Jc(B,T) curves of the films, when the pinning site distributions...... are taken from distributions of twin spacings and BZO nanorods from transmission electron microscope images. Thus, assuming that the model can be used for prediction of the Jc properties, we conclude that for enhancement of undoped films more crystalline defects are needed and for doped films a dopant...

  1. Co-sputtered ZnO:Si thin films as transparent conductive oxides

    Energy Technology Data Exchange (ETDEWEB)

    Faure, C. [CNRS, Univ. Bordeaux, ICMCB, UPR 9048, F33600 Pessac (France); Clatot, J. [LRCS, 33 Rue St Leu, F-80039 Amiens (France); Teule-Gay, L.; Campet, G. [CNRS, Univ. Bordeaux, ICMCB, UPR 9048, F33600 Pessac (France); Labrugere, C. [CeCaMA, Universite de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, Pessac, F-33608 (France); Nistor, M. [National Institute for Lasers, Plasmas and Radiation Physics, L22, PO Box MG-36, 77125 Bucharest-Magurele (Romania); Rougier, A., E-mail: rougier@icmcb-bordeaux.cnrs.fr [CNRS, Univ. Bordeaux, ICMCB, UPR 9048, F33600 Pessac (France)

    2012-12-01

    Silicon doped Zinc Oxide thin films, so-called SZO, were deposited at room temperature on glass and plastic substrates by co-sputtering of ZnO and SiO{sub 2} targets. The influence of the SiO{sub 2} target power supply (from 30 to 75 W) on the SZO thin film composition and crystallinity is discussed. Si/Zn atomic ratio, determined by X-ray microprobe, increases from 1.2 to 8.2 at.%. For Si/Zn ratio equal and lower than 3.9%, SZO (S{sub 3.9}ZO) thin films exhibit the Wurzite structure with the (0 0 2) preferred orientation. Larger Si content leads to a decrease in crystallinity. With Si addition, the resistivity decreases down to 3.5 Multiplication-Sign 10{sup -3} Ohm-Sign {center_dot}cm for SZO thin film containing 3.9 at.% of Si prior to an increase. The mean transmittance of S{sub 3.9}ZO thin film on glass substrate approaches 80% (it is about 90% for the film itself) in the visible range (from 400 to 750 nm). Co-sputtered SZO thin films are suitable candidates for large area transparent conductive oxides. - Highlights: Black-Right-Pointing-Pointer Si doped ZnO thin films by co-sputtering of ZnO and SiO{sub 2} targets. Black-Right-Pointing-Pointer Minimum of resistivity for Si doped ZnO thin films containing 3.9% of Si. Black-Right-Pointing-Pointer Si and O environments by X-ray Photoelectron Spectroscopy.

  2. Fabrication of BaTiO3/Ni composite particles and their electro-magneto responsive properties

    International Nuclear Information System (INIS)

    Lu, Yaping; Gao, Lingxiang; Wang, Lijuan; Xie, Zunyuan; Gao, Meixiang; Zhang, Weiqiang

    2017-01-01

    Graphical abstract: The spherical BaTiO 3 /Ni particles with excellent structure were made by one-step method through fixing the metal Ni(0) reduced by a specific reducing agent (N 2 H 4 ·H 2 O) on the surface of the BaTiO 3 particles with grain diameter of ∼500 nm. BaTiO 3 /Ni particle has double responses of electric and magnetic field simultaneously. Consequentially, coating magnetic metal on BT particle is proposed an effective method to prepare novel electro-magneto responsive particles and one basis of electro-magneto responsive elastomers. - Highlights: • The BaTiO 3 /Ni composite particles were fabricated. • The content of Ni(0) in nickel sheath is 70.2%. • The BaTiO 3 /Ni particles have double responses of electric and magnetic field. - Abstract: BaTiO 3 (BT)/Ni composite particles were made by one-step method through agglomerating the metal Ni(0) nanoparticles reduced by a specific reducing agent (N 2 H 4 ·H 2 O) on the surface of BT sphere with diameter of ∼500 nm. The BT/Ni composite particles were characterized by the means of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). In BT/Ni particles, pure BT spherical particle was coated with Ni nanoparticles agglomerated on its surface. The average thickness of the Ni sheath was ∼30 nm and the content of Ni(0) and Ni (II) in the sheath were 70.2% and 29.8%, respectively. The responsive effects of BT/Ni particles filled in hydrogel elastomer were investigated by the viscoelastic properties. The results indicate that the BT/Ni particles exhibit electro and magneto coordinated responsive properties (E = 1 kV/mm, H = 0.1 T/mm), which is superior to BT particles with individual electro response.

  3. Magnetron sputtered Cu{sub 3}N/NiTiCu shape memory thin film heterostructures for MEMS applications

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Navjot; Choudhary, Nitin [Indian Institute of Technology Roorkee, Roorkee, Functional Nanomaterials Research Lab, Department of Physics and Centre of Nanotechnology (India); Goyal, Rajendra N. [Indian Institute of Technology, Roorkee, Department of Chemistry (India); Viladkar, S. [Indian Institute of Technology Roorkee, Roorkee, Functional Nanomaterials Research Lab, Department of Physics and Centre of Nanotechnology (India); Matai, I.; Gopinath, P. [Indian Institute of Technology, Roorkee, Centre for Nanotechnology (India); Chockalingam, S. [Indian Institute of Technology, Guwahati, Department of Biotechnology (India); Kaur, Davinder, E-mail: dkaurfph@iitr.ernet.in [Indian Institute of Technology Roorkee, Roorkee, Functional Nanomaterials Research Lab, Department of Physics and Centre of Nanotechnology (India)

    2013-03-15

    In the present study, for the first time, Cu{sub 3}N/NiTiCu/Si heterostructures were successfully grown using magnetron sputtering technique. Nanocrystalline copper nitride (Cu{sub 3}N with thickness {approx}200 nm) thin films and copper nanodots were subsequently deposited on the surface of 2-{mu}m-thick NiTiCu shape memory thin films in order to improve the surface corrosion and nickel release properties of NiTiCu thin films. Interestingly, the phase transformation from martensite phase to austenite phase has been observed in Cu{sub 3}N/NiTiCu heterostructures with corresponding change in texture and surface morphology of top Cu{sub 3}N films. Field emission scanning electron microscopy and atomic force microscope images of the heterostructures reveals the formation of 20-nm-sized copper nanodots on NiTiCu surface at higher deposition temperature (450 Degree-Sign C) of Cu{sub 3}N. Cu{sub 3}N passivated NiTiCu films possess low corrosion current density with higher corrosion potential and, therefore, better corrosion resistance as compared to pure NiTiCu films. The concentration of Ni released from the Cu{sub 3}N/NiTiCu samples was observed to be much less than that of pure NiTiCu film. It can be reduced to the factor of about one-ninth after the surface passivation resulting in smooth, homogeneous and highly corrosion resistant surface. The antibacterial and cytotoxicity of pure and Cu{sub 3}N coated NiTiCu thin films were investigated through green fluorescent protein expressing E. coli bacteria and human embryonic kidney cells. The results show the strong antibacterial property and non cytotoxicity of Cu{sub 3}N/NiTiCu heterostructure. This work is of immense technological importance due to variety of BioMEMS applications.

  4. Thickness-dependent piezoelectric behaviour and dielectric properties of lanthanum modified BiFeO3 thin films

    Directory of Open Access Journals (Sweden)

    Glenda Biasotto

    2011-03-01

    Full Text Available Bi0.85La0.15FeO3 (BLFO thin films were deposited on Pt(111/Ti/SiO2 /Si substrates by the soft chemical method. Films with thicknesses ranging from 140 to 280 nm were grown on platinum coated silicon substrates at 500°C for 2 hours. The X-ray diffraction analysis of BLFO films evidenced a hexagonal structure over the entire thickness range investigated. The grain size of the film changes as the number of the layers increases, indicating thickness dependence. It is found that the piezoelectric response is strongly influenced by the film thickness. It is shown that the properties of BiFeO3 thin films, such as lattice parameter, dielectric permittivity, piezoeletric coefficient etc., are functions of misfit strains.

  5. Investigation of growth, structural and electronic properties of V{sub 2}O{sub 3} thin films on selected substrates

    Energy Technology Data Exchange (ETDEWEB)

    Nateprov, Alexei

    2006-08-15

    The present work is devoted to the experimental study of the MI transition in V{sub 2}O{sub 3} thin films, grown on different substrates. The main goal of the work was to develop a technology of growth of V{sub 2}O{sub 3} thin films on substrates with different electrical and structural properties (diamond and LiNbO{sub 3}), designed for specific applications. The structural and electrical properties of the obtained films were characterized in detail with a special focus on their potential applications. The MIT of V{sub 2}O{sub 3} was investigated by SAW using first directly deposited V{sub 2}O{sub 3} thin film onto a LiNbO{sub 3} substrate. (orig.)

  6. Enhancement of polarization property of silane-modified BaTiO3 nanoparticles and its effect in increasing dielectric property of epoxy/BaTiO3 nanocomposites

    Directory of Open Access Journals (Sweden)

    Thi Tuyet Mai Phan

    2016-03-01

    Full Text Available The surface modification of synthesized nano-BaTiO3 particles was carried out using γ-aminopropyl trimethoxy silane (γ-APS in an ethanol/water solution. The modified particles were characterized by FTIR, TGA, surface charge analysis, and by dielectric constant measurement. The silane molecules were attached to the surface of BaTiO3 particles through SiOBaTiO3 bonds. The γ-APS grafted on BaTiO3 made the dielectric constant of the particles increase at frequencies ≥0.3 kHz in a wide range of temperature (25 °C–140 °C, due to the presence of NH2 groups. The dependence of the polarization vs. electrical field was measured in order to elucidate the dielectric behavior of the silane treated BaTiO3 in comparison to untreated BaTiO3. The nanocomposite based on epoxy resin containing BaTiO3 nanoparticles untreated and treated with γ-APS was also prepared and characterized. The results indicated that the γ-APS-modified BaTiO3 surfaces significantly enhanced the dielectric property of the nanocomposite.

  7. Study on the Preparation and Properties of Colored Iron Oxide Thin Films

    International Nuclear Information System (INIS)

    Zhao Xianhui; Li Changhong; Liu Qiuping; He Junjing; Wang Hai; Liang Song; Duan Yandong; Liu Su

    2013-01-01

    Colored iron oxide thin films were prepared using Sol-gel technique. The raw materials were tetraethyl orthosilicate (TEOS), etoh ehanol (EtOH), iron nitrate, and de-ionized water. Various properties were measured and analysed, including the colour of thin films, surface topography, UV-Visible spectra, corrosion resistance and hydrophobicity. To understand how these properties influenced the structural and optical properties of Fe 2 O 3 thin films, Scanning Electron Microscope (SEM), UV Spectrophotometer and other facilities were employed. Many parameters influence the performance of thin films, such as film layers, added H 2 O content, and the amount of polydimethylsiloxane (PDMS). When the volume ratio of TEOS, EtOH and H 2 O was 15: 13: 1, the quality of Fe(NO 3 ) 3 ·9H 2 O was 6g, and pH value was 3, reddish and uniform Fe 2 O 3 thin films with excellent properties were produced. Obtained thin films possessed corrosion resistance in hydrochloric acid with pH=l and the absorption edge wavelength was ∼350.2nm. Different H 2 O contents could result in different morphologies of Fe 2 O 3 nanoparticles. When 1.5 ml PDMS was added into the Sol, thin films possessed hydrophobiliry without dropping. Coating with different layers, thin films appeared different morphologies. Meanwhile, with the increment of film layers, the absorbance increased gradually.

  8. Growth and magnetic properties of multiferroic LaxBi1-xMnO3 thin films

    Science.gov (United States)

    Gajek, M.; Bibes, M.; Wyczisk, F.; Varela, M.; Fontcuberta, J.; Barthélémy, A.

    2007-05-01

    A comparative study of LaxBi1-xMnO3 thin films grown on SrTiO3 substrates is reported. It is shown that these films grow epitaxially in a narrow pressure-temperature range. A detailed structural and compositional characterization of the films is performed within the growth window. The structure and the magnetization of this system are investigated. We find a clear correlation between the magnetization and the unit-cell volume that we ascribe to Bi deficiency and the resultant introduction of a mixed valence on the Mn ions. On these grounds, we show that the reduced magnetization of LaxBi1-xMnO3 thin films compared to the bulk can be explained quantitatively by a simple model, taking into account the deviation from nominal composition and the Goodenough-Kanamori-Anderson rules of magnetic interactions.

  9. Vacancy defects in epitaxial La0.7Sr0.3MnO3 thin films probed by a slow positron beam

    International Nuclear Information System (INIS)

    Jin, S W; Zhou, X Y; Wu, W B; Zhu, C F; Weng, H M; Wang, H Y; Zhang, X F; Ye, B J; Han, R D

    2004-01-01

    Vacancy defects in epitaxial La 0.7 Sr 0.3 MnO 3 (LSMO) thin films on LaAlO 3 substrates were detected using a variable energy positron beam. The line-shape S parameter of the epitaxial thin films deposited at different oxygen pressures was measured as a function of the implanting positron energy E. Our results show that the S parameter of the films changes non-monotonically with their deposition oxygen pressures. For the films deposited at lower oxygen pressures, the increase in S value in the films is attributed to the increase in oxygen vacancies and/or related defect-V O complexes, and for those deposited at higher oxygen pressures, the larger S parameter of the films is caused by the grain boundaries and/or metallic ion vacancies. The surface morphology of the films was also characterized to analyse the open volume defects in the LSMO films

  10. Influence of γ-radiation doses on the properties of TeOx: (x=2-3) thin film

    International Nuclear Information System (INIS)

    Dewan, Namrata; Sreenivas, K.; Gupta, Vinay

    2007-01-01

    The influence of γ-ray doses (10-50 Gy) on the optical and electrical properties of radio-frequency sputtered tellurium dioxide (TeO x ) thin film was studied. The composition of the as-deposited TeO x films deposited under 25% oxygen and 100% oxygen in the sputtering gas mixture (Ar+O 2 ) was x=2 and 3, respectively. TeO 3 films were found to be highly sensitive to the γ-radiation doses and the value of optical band gap decrease from 4.18 to 3.56 eV with increasing radiation dose from 10 to 50 Gy. Current-voltage characteristics of the films showed an increase in the value of conductivity with increasing radiation doses. Monotonic decrease in the values of dielectric constant for the deposited films with increase in radiation dose was observed. The effect of γ-ray doses on the properties of TeO x film has been correlated with the rearrangement of the bipyramidal structure of amorphous TeO x thin film

  11. Thin film metal-oxides

    CERN Document Server

    Ramanathan, Shriram

    2009-01-01

    Presents an account of the fundamental structure-property relations in oxide thin films. This title discusses the functional properties of thin film oxides in the context of applications in the electronics and renewable energy technologies.

  12. Low-field tunnel-type magnetoresistance properties of polycrystalline and epitaxial La sub 0 sub . sub 6 sub 7 Sr sub 0 sub . sub 3 sub 3 MnO sub 3 thin films

    CERN Document Server

    Shim, I B; Choi, S Y

    2000-01-01

    The low-field tunnel-type magnetoresistance (TMB) properties of sol-gel derived polycrystalline and epitaxial La sub 0 sub . sub 6 sub 7 Sr sub 0 sub . sub 3 sub 3 MnO sub 3 (LSMO) thin films were investigated. The polycrystalline thin films were fabricated on Si (100) with a thermally oxidized SiO sub 2 layer while the epitaxial thin films were grown on LaAlO sub 3 (001) single-crystal substrates. The epitaxial thin films displayed both typical intrinsic colossal magnetoresistance (CMR) and abnormal extrinsic tunnel-type magnetoresistance behaviors. Tunnel-type MR ratio as high as 0.4% were observed in the polycrystalline thin films at a field of 120 Oe at room temperature (300 K) whereas the ratios were less than 0.1% for the epitaxial films in the same field range. The low-field tunnel-type MR of polycrystalline LSMO/SiO sub 2 ?Si (100) thin films originated from the behaviors of the grain-boundary properties.

  13. Luminescence enhancement of ZnO-poly(methylmethacrylate) nanocomposite films by incorporation of crystalline BaTiO_3 nanoparticles

    International Nuclear Information System (INIS)

    Kanamori, Tsuyoshi; Han, Yu; Nagao, Daisuke; Kamezawa, Nao; Ishii, Haruyuki; Konno, Mikio

    2016-01-01

    Highlights: • Dielectric barium titanate (BT) nanoparticles incorporated into luminescence films. • Luminescence intensities increased by the BT nanoparticle incorporation. • Incorporation of highly dielectric nanoparticles effective for luminescence enhancement. - Abstract: Incorporation of highly dielectric nanoparticles into luminescent ZnO-polymethylmethacrylate (PMMA) nanocomposite films was undertaken to examine the effect of nanoparticle incorporation on luminescence intensity of the nanocomposite films. ZnO nanoparticles were prepared as inorganic phosphors by a precipitation method. The ZnO nanoparticles were then surface-modified with 3-methacryloxypropyltrimethoxysilane (MPTMS) to be used for fabrication of the ZnO-PMMA nanocomposite film. Barium titanate (BT) nanoparticles were synthesized with a sol-gel method as the highly dielectric nanoparticles, which were also surface-modified with the MPTMS for the incorporation into the nanocomposite films. Luminescence intensity of the nanocomposite films was successfully increased by the nanoparticle incorporation up to a BT content around 15 vol%. The luminescence intensity higher than that measured for the nanocomposite films incorporating SiO_2 nanoparticles indicated that the incorporation of highly dielectric nanoparticles was an effective approach to enhance the luminescence of ZnO nanoparticles in the polymer thin films.

  14. Epitaxial growth and magnetic properties of ultraviolet transparent Ga2O3/(Ga1−xFex)2O3 multilayer thin films

    Science.gov (United States)

    Guo, Daoyou; An, Yuehua; Cui, Wei; Zhi, Yusong; Zhao, Xiaolong; Lei, Ming; Li, Linghong; Li, Peigang; Wu, Zhenping; Tang, Weihua

    2016-01-01

    Multilayer thin films based on the ferromagnetic and ultraviolet transparent semiconductors may be interesting because their magnetic/electronic/photonic properties can be manipulated by the high energy photons. Herein, the Ga2O3/(Ga1−xFex)2O3 multilayer epitaxial thin films were obtained by alternating depositing of wide band gap Ga2O3 layer and Fe ultrathin layer due to inter diffusion between two layers at high temperature using the laser molecular beam epitaxy technique. The multilayer films exhibits a preferred growth orientation of crystal plane, and the crystal lattice expands as Fe replaces Ga site. Fe ions with a mixed valence of Fe2+ and Fe3+ are stratified distributed in the film and exhibit obvious agglomerated areas. The multilayer films only show a sharp absorption edge at about 250 nm, indicating a high transparency for ultraviolet light. What’s more, the Ga2O3/(Ga1−xFex)2O3 multilayer epitaxial thin films also exhibits room temperature ferromagnetism deriving from the Fe doping Ga2O3. PMID:27121446

  15. Ferroelectric properties of barium strontium titanate thin films grown by RF co-sputtering

    International Nuclear Information System (INIS)

    Zapata-Navarro, A.; Marquez-Herrera, A.; Cruz-Jauregui, M.P.; Calzada, M.L.

    2005-01-01

    In this work, we present the variation of the ferroelectric properties of Ba 1-x Sr x TiO 3 films deposited on Pt/TiO 2 /SiO 2 /Si substrates by RF co-sputtering with 0≤x≤1. The co-sputtering was done using a single magnetron with BaTiO 3 /SrTiO 3 targets in a pie mosaics configuration. Smooth and uniform films were obtained using the same conditions of growth and annealing temperature. The X-ray diffraction and EDS results show that the processes were managed to obtain crystalline materials with x from 0 to 1. The behaviour of P-E loops suggests that the ferroelectric properties of the films were tuned by changing the concentration of the cation. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Electrical Transport and Magnetoresistance Properties of Tensile-Strained CaMnO3 Thin Films

    Science.gov (United States)

    Ullery, Dustin; Lawson, Bridget; Zimmerman, William; Neubauer, Samuel; Chaudhry, Adeel; Hart, Cacie; Yong, Grace; Smolyaninova, Vera; Kolagani, Rajeswari

    We will present our studies of the electrical transport and magnetoresistance properties of tensile strained CaMnO3 thin films. We observe that the resistivity decreases significantly as the film thickness decreases which is opposite to what is observed in thin films of hole doped manganites. The decrease in resistivity is more pronounced in the films on (100) SrTiO3, with resistivity of the thinnest films being about 3 orders of magnitude lower than that of bulk CaMnO3. Structural changes accompanying resistivity changes cannot be fully explained as due to tensile strain, and indicate the presence of oxygen vacancies. These results also suggest a coupling between tensile strain and oxygen deficiency, consistent with predictions from models based on density functional theory calculations. We observe a change in resistance under the application of moderate magnetic field. Experiments are underway to understand the origin of the magnetoresistance and its possible relation to the tensile strain effects. We acknowledge support from: Towson Office of University Undergraduate Research, Fisher Endowment Grant and Undergraduate Research Grants from the Fisher College of Science and Mathematics, and Seed Funding Grant from the School of Emerging technologies.

  17. Photo- and Electrochromic Properties of Activated Reactive Evaporated MoO3 Thin Films Grown on Flexible Substrates

    Directory of Open Access Journals (Sweden)

    K. Hari Krishna

    2008-01-01

    Full Text Available The molybdenum trioxide (MoO3 thin films were grown onto ITO-coated flexible Kapton substrates using plasma assisted activated reactive evaporation technique. The film depositions were carried out at constant glow power and oxygen partial pressures of 8 W and 1×10−3 Torr, respectively. The influence of substrate temperature on the microstructural and optical properties was investigated. The MoO3 thin films prepared at a substrate temperature of 523 K were found to be composed of uniformly distributed nanosized grains with an orthorhombic structure of α-MoO3. These nanocrystalline MoO3 thin films exhibited higher optical transmittance of about 80% in the visible region with an evaluated optical band gap of 3.29 eV. With the insertion of 12.5 mC/cm2, the films exhibited an optical modulation of 40% in the visible region with coloration efficiency of 22 cm2/C at the wavelength of 550 nm. The MoO3 films deposited at 523 K demonstrated better photochromic properties and showed highest color center concentration for the irradiation time of 30 minutes at 100 mW/cm2.

  18. Fabrication and electrical investigations of Pb-doped BaTiO_3 ceramics

    International Nuclear Information System (INIS)

    Sareecha, N.; Shah, W.A.; Maqsood, A.; Anis-ur-Rehman, M.; Latif Mirza, M.

    2017-01-01

    Electrical properties of Pb doped BaTiO_3; PBT are investigated in the wide range of temperatures (40–700 °C) at 1 kHz frequency. PBT ceramics were fabricated through solid state sintering method. Pre fired BaTiO_3 prepared with Ba/Ti molar ratio of 0.98 was doped with PbCO_3 (<1 mole %). XRD patterns indicated perovskite phase with tetragonal structures (P4mm). Morphological studies (SEM) revealed grain development with increasing lead contents. With lead doping and its variation, Curie temperature (T_C) was shifted from 120 to 200 °C with broad dielectric constant peaks and dielectric anomalies with relaxor behavior were observed. Resistivity decreased with increasing temperature, all specimens showed semiconductor behavior with negative temperature coefficient of resistivity (NTCR) characteristics. Mobility of electrons increased with thermal activation due to hopping of charge carriers from one site to another. Ohmic conductivities and associated activation energies were evaluated by impedance spectroscopy. Conductivity followed the Arrhenius law with E_a = 1.187–1.169 eV which can be attributed to the ionic conduction owning to doubly ionized oxygen vacancies. Well-defined hysteresis P-E loops measured at room temperature depicted ferroelectric properties of the materials. - Graphical abstract: Temperature dependence of dielectric constant (Ɛ′) and resistivity (ρ) for pure and Pb-doped BaTiO_3 ceramics at 1 k Hz frequency. - Highlights: • Pb-doped BaTiO_3ceramics were fabricated through solid state sintering. • Electrical properties were studied at the temperatures 40–700 °C at 1 kHz. • Specimens showed negative temperature coefficient of resistivity characteristics. • Conductivity followed the Arrhenius law with E_a = 1.187–1.169 eV. • Ionic conduction was supposed to be responsible for conduction process.

  19. Photon up-converting (Yb,Er){sub 2}O{sub 3} thin films by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Tuomisto, Minnea [Department of Chemistry, University of Turku (Finland); Doctoral Programme in Physical and Chemical Sciences, University of Turku Graduate School (UTUGS), Turku (Finland); Giedraityte, Zivile; Karppinen, Maarit [Department of Chemistry and Materials Science, School of Chemical Engineering, Aalto University (Finland); Lastusaari, Mika [Department of Chemistry, University of Turku (Finland); Turku University Centre for Materials and Surfaces (MatSurf), Turku (Finland)

    2017-06-15

    We report up-converting (Yb,Er){sub 2}O{sub 3} thin films grown with the atomic layer deposition (ALD) technique. The films are crystalline and show a homogeneous morphology with a roughness less than 1 nm for 40 nm thick films. High-intensity near-infrared (NIR) to green and red two-photon up-conversion emission is obtained with 974 nm excitation through an absorption by Yb{sup 3+}, followed by a Yb{sup 3+}-Er{sup 3+} energy transfer and emission from Er{sup 3+}. The ALD technique promises to be excellent for producing up-converting films for many applications such as near-infrared radiation absorbing layers for solar cells and sensors in point-of-care biomedical diagnostics. Schematic picture of the ALD-grown (Yb,Er){sub 2}O{sub 3} thin film including the up-conversion emission spectra. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Thin films and nanomaterials

    International Nuclear Information System (INIS)

    Jayakumar, S.; Kannan, M.D.; Prasanna, S.

    2012-01-01

    The objective of this book is to disseminate the most recent research in Thin Films, Nanomaterials, Corrosion and Metallurgy presented at the International Conference on Advanced Materials (ICAM 2011) held in PSG College of Technology, Coimbatore, India during 12-16 December 2011. The book is a compilation of 113 chapters written by active researchers providing information and critical insights into the recent advancements that have taken place. Important new applications are possible today in the fields of microelectronics, opto-electronics, metallurgy and energy by the application of thin films on solid surfaces. Recent progress in high vacuum technology and new materials has a remarkable effect in thin film quality and cost. This has led to the development of new single or multi-layered thin film devices with diverse applications in a multitude of production areas, such as optics, thermal barrier coatings and wear protections, enhancing service life of tools and to protect materials against thermal and atmospheric influence. On the other hand, thin film process techniques and research are strongly related to the basic research activities in nano technology, an increasingly important field with countless opportunities for applications due to the emergence of new properties at the nanoscale level. Materials and structures that are designed and fabricated at the nano scale level, offer the potential to produce new devices and processes that may enhance efficiencies and reduce costs in many areas, as photovoltaic systems, hydrogen storage, fuel cells and solar thermal systems. In the book, the contributed papers are classified under two sections i) thin films and ii) nanomaterials. The thin film section includes single or multi layer conducting, insulating or semiconducting films synthesized by a wide variety of physical or chemical techniques and characterized or analyzed for different applications. The nanomaterials section deals with novel or exciting materials

  1. New Method for Fabrication of Co3O4 Thin Film Sensors: Structural, Morphological and Optoelectronic Properties

    Directory of Open Access Journals (Sweden)

    Vikas PATIL

    2011-05-01

    Full Text Available Nanocrystalline Co3O4 thin films have been deposited by spin coating technique and then have been analyzed to test their application in NH3 gas-sensing technology. In particular, spectrophotometric and conductivity measurements have been performed in order to determine the optical and electrical properties of Co3O4 thin films. The structure and the morphology of such material have been investigated by X ray diffraction and Scanning electron microscopy. The X-ray diffraction studies confirmed that the films grown by this technique have good crystalline cubic spinel structure and present a random orientation. The morphology of the sol gel derived Co3O4 shows nanocrystalline grains with some overgrown clusters .The optical band gap has been determined from the absorption coefficient. We found that the optical band gap energy decreases from 2.58 eV to 2.07 eV with increasing annealing temperature between 400-700 oC. These mean that the optical quality of Co3O4 films is improved by annealing. The dc electrical conductivity of Co3O4 thin films were increased from 10-4 to 10-2(Ω cm-1 with increase in annealing temperature. The electron carrier concentration (n and mobility (μ of Co3O4 films annealed at 400-700 oC were estimated to be of the order of 2.4 to 4.5 x 1019 cm-3 and 5.2 to 7.0 x 10-5 cm2 V-1 s-1 respectively. It is observed that Co3O4 thin film annealing at 700 oC after deposition provide a smooth and flat texture suited for optoelectronic applications. Gas sensing properties showed that the Co3O4 films (at 700 oC were sensitive as well as fast in responding to NH3. A high sensitivity for ammonia indicates that the Co3O4 films are selective for this gas.

  2. Nb{sub 3}Al thin film deposition for low-noise terahertz electronics

    Energy Technology Data Exchange (ETDEWEB)

    Dochev, D; Pavolotsky, A B; Belitsky, V; Olofsson, H [Group for Advanced Receiver Development and Onsala Space Observatory, Department of Radio- and Space Science, Chalmers University of Technology, SE 412 96 Gothenburg (Sweden)], E-mail: dimitar.dochev@chalmers.se

    2008-02-01

    Higher energy gap superconducting materials were always interesting for low-noise mixer applications such as superconductor-insulator-superconductor tunnel junctions (SIS) and hot-electron bolometer (HEB) used in sub-millimeter and terahertz parts of electro-magnetic spectrum. Here, we report a novel approach for producing Nb{sub 3}Al thin film by co-sputtering from two confocally arranged Nb and Al dc-magnetrons onto substrate heated up to 830 deg. C. Characterization of the deposited films revealed presence of the A15 phase and measured critical temperature was up to 15.7 K with the transition width 0.2-0.3 K for a 300 nm thick film. We measured the film critical magnetic field and studied influence of annealing on the film properties. We have investigated compositional depth profile of the deposited films by spectroscopy of reflected electrons.

  3. Transport and magnetic properties of Ce-doped LaMnO3 thin films

    International Nuclear Information System (INIS)

    Yanagida, Takeshi; Kanki, Teruo; Vilquin, Bertrand; Tanaka, Hidekazu; Kawai, Tomoji

    2005-01-01

    Ce-doped LaMnO 3 epitaxial thin films were fabricated by a pulsed laser deposition method in consideration of thermodynamics. Oxygen- or argon-atmosphere post-annealed films showed a metal-insulator transition and ferromagnetic property, and the transition temperature T c was found to be significantly influenced by the post-annealing conditions at the T c ranging from 200 to 300 K. Moreover, the majority carriers within Ce-doped LaMnO 3 films were identified to be holes from Hall effect measurements

  4. Polarization-tuned diode behaviour in multiferroic BiFeO3 thin films

    KAUST Repository

    Yao, Yingbang; Zhang, Bei; Chen, Long; Yang, Yang; Wang, Zhihong; Alshareef, Husam N.; Zhang, Xixiang

    2012-01-01

    Asymmetric rectifying I-V behaviour of multiferroic BiFeO3 (BFO) thin films grown on transparent ITO-coated glass was quantitatively studied as a function of ferroelectric polarization. Different polarized states were established by unipolar

  5. Structural and photodegradation behaviors of Fe{sup 3+}-doping TiO{sub 2} thin films prepared by a sol–gel spin coating

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Huey-Jiuan; Yang, Tien-Syh [Department of Materials Science and Engineering, National United University, 1 Lien-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China); Wang, Moo-Chin, E-mail: mcwang@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 80782, Taiwan (China); Hsi, Chi-Shiung, E-mail: chsi@nuu.edu.tw [Department of Materials Science and Engineering, National United University, 1 Lien-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China)

    2014-10-15

    Highlights: • Pure and various Fe{sup 3+}-doped TiO{sub 2} thin films have been successfully fabricated. • The phase of all thin films was single phase of anatase TiO{sub 2} when calcined at 823 K. • The crystallinity of TiO{sub 2} thin films decreased as Fe{sup 3+}-doping increased. • The photodegradation of each sample increased as the irradiation time increased. • The photodegradation increased as Fe{sup 3+}-doping increased at a fixed irradiation time. - Abstract: Pure and various Fe{sup 3+}-doping TiO{sub 2} thin films have been successfully fabricated on glass substrate prepared by a sol–gel spin coating route. The structural and photodegradation behavior of these films after calcined at various temperatures for 1 h were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectrum and degradation of 1.0 × 10{sup −5} M methylene blue solution. When all thin films after calcined at 823 K for 1 h, the crystalline phase are comprised only contained single phase of anatase TiO{sub 2}. The crystallinity of various Fe{sup 3+}-doping TiO{sub 2} thin films decreases with Fe{sup 3+}-doping concentration increased. The PL intensity of all thin films also decreases with Fe{sup 3+}-doping concentration increased. When all various Fe{sup 3+}-doping TiO{sub 2} thin films after calcined at 823 K for 1 h, the photodegradation of each sample increases with irradiation time increased. Moreover, the photodegradation also increases with Fe{sup 3+}-doping concentration increased when fixed at constant irradiation time.

  6. Epitaxial La2/3Sr1/3MnO3 thin films with unconventional magnetic and electric properties near the Curie temperature

    International Nuclear Information System (INIS)

    Signorini, L.; Riva, M.; Cantoni, M.; Bertacco, R.; Ciccacci, F.

    2006-01-01

    We used Pulsed Laser Deposition (PLD) in oxidizing environment to epitaxially grow optimally doped manganite La 2/3 Sr 1/3 MnO 3 (LSMO) thin films over a (001) oriented SrTiO 3 substrate. Synthesized samples show good room temperature magnetic properties accompanied by a peculiar extension of the metallic conduction regime to temperatures higher than the Curie point. In this paper we present a study of the dependence of transport and magnetic properties of LSMO thin films on the oxygen pressure during PLD growth. We show how interaction of the growing films with O 2 molecules is fundamental for a correct synthesis and in which way it is possible to adjust PLD experimental parameters in order to tune LSMO thin film properties. The persistence of the metallic conduction regime above the Curie temperature indicates some minor changes of the electronic structure near the Fermi level, which is responsible for the half-metallic behavior of LSMO at low temperature. This feature is rather intriguing from the technological point of view, as it could pave the way to the increase of operating temperature of devices based on LSMO

  7. Comparison of Y{sub 2}O{sub 3}:Bi{sup 3+} phosphor thin films fabricated by the spin coating and radio frequency magnetron techniques

    Energy Technology Data Exchange (ETDEWEB)

    Jafer, R.M.; Yousif, A. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Department of Physics, Faculty of Education, University of Khartoum, P.O. Box 321, Postal Code 11115 Omdurman (Sudan); Kumar, Vinod [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Photovoltaic Laboratory, Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110016 (India); Pathak, Trilok Kumar [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Semiconductor Physics Lab, Department of Physics, Gurukula Kangri University, Haridwar (India); Purohit, L.P. [Semiconductor Physics Lab, Department of Physics, Gurukula Kangri University, Haridwar (India); Swart, H.C., E-mail: swarthc@ufs.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Coetsee, E., E-mail: CoetseeE@ufs.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa)

    2016-09-15

    The reactive radio-frequency (RF) magnetron sputtering and spin coating fabrication techniques were used to fabricate Y{sub 2−x}O{sub 3}:Bi{sub x=0.5%} phosphor thin films. The two techniques were analysed and compared as part of investigations being done on the application of down-conversion materials for a Si solar cell. The morphology, structural and optical properties of these thin films were investigated. The X-ray diffraction results of the thin films fabricated by both techniques showed cubic structures with different space groups. The optical properties showed different results because the Bi{sup 3+} ion is very sensitive towards its environment. The luminescence results for the thin film fabricated by the spin coating technique is very similar to the luminescence observed in the powder form. It showed three obvious emission bands in the blue and green regions centered at about 360, 410 and 495 nm. These emissions were related to the {sup 3}P{sub 1}–{sup 1}S{sub 0} transition of the Bi{sup 3+} ion situated in the two different sites of the Y{sub 2}O{sub 3} matrix with I a-3(206) space group. Whereas the thin film fabricated by the radio frequency magnetron technique showed a broad single emission band in the blue region centered at about 416 nm. This was assigned to the {sup 3}P{sub 1}–{sup 1}S{sub 0} transition of the Bi{sup 3+} ion situated in one of the Y{sub 2}O{sub 3} matrix's sites with a Fm-3 (225) space group. The spin coating fabrication technique is suggested to be the best technique to fabricate the Y{sub 2}O{sub 3}:Bi{sup 3+} phosphor thin films. - Highlights: • RF sputtering and spin coating were used to fabricate Y{sub 2−x}O{sub 3}:Bi{sub x=0.5%} phosphor thin films. • XRD results of the two films showed cubic structures with different space groups. • PL showed different emission for the Bi{sup 3+} ions in the two films. • Three emission bands in the blue and green regions centered at about 360, 410 and 495 nm. • RF

  8. Epitaxial thin-film growth of Ruddlesden-Popper-type Ba3Zr2O7 from a BaZrO3 target by pulsed laser deposition

    International Nuclear Information System (INIS)

    Butt, Shariqa Hassan; Rafique, M.S.; Siraj, K.; Latif, A.; Afzal, Amina; Awan, M.S.; Bashir, Shazia; Iqbal, Nida

    2016-01-01

    Ruddlesden-Popper Ba 3 Zr 2 O 7 thin films have been synthesized via pulsed laser deposition (PLD) technique. The optimization of deposition parameters in PLD enables the formation of thin film of metastable Ba 3 Zr 2 O 7 phase from BaZrO 3 target. In order to see the post-annealing effects on the structural and optical properties, the deposited Ba 3 Zr 2 O 7 thin films were annealed at 500, 600 and 800 C. X-ray diffraction (XRD) reveals the formation of Ba 3 Zr 2 O 7 phase with tetragonal structure. The changes in the surface of the deposited films were analysed by FE-SEM and AFM. The thin film post-annealed at 500 C exhibited the best structural, optical and surface properties. Furthermore, the chemical states and chemical composition of the films were determined by X-ray photoelectron spectroscopy (XPS) near the surface. The XPS results show that Ba, Zr and O exist mainly in the form of Ba 3 Zr 2 O 7 Ruddlesden-Popper-type perovskite structure. (orig.)

  9. Multiple Interfacial Fe3O4@BaTiO3/P(VDF-HFP) Core-Shell-Matrix Films with Internal Barrier Layer Capacitor (IBLC) Effects and High Energy Storage Density.

    Science.gov (United States)

    Zhou, Ling; Fu, Qiuyun; Xue, Fei; Tang, Xiahui; Zhou, Dongxiang; Tian, Yahui; Wang, Geng; Wang, Chaohong; Gou, Haibo; Xu, Lei

    2017-11-22

    Flexible nanocomposites composed of high dielectric constant fillers and polymer matrix have shown great potential for electrostatic capacitors and energy storage applications. To obtain the composited material with high dielectric constant and high breakdown strength, multi-interfacial composited particles, which composed of conductive cores and insulating shells and possessed the internal barrier layer capacitor (IBLC) effect, were adopted as fillers. Thus, Fe 3 O 4 @BaTiO 3 core-shell particles were prepared and loaded into the poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) polymer matrix. As the mass fraction of core-shell fillers increased from 2.5 wt % to 30 wt %, the dielectric constant of the films increased, while the loss tangent remained at a low level (capacitor model was also adopted to interpret the efficiency of IBLC effects on the suppressed loss tangent and the superior breakdown strength. This work explored an effective approach to prepare dielectric nanocomposites for energy storage applications experimentally and theoretically.

  10. Growth and physical properties of highly oriented La-doped (K,Na)NbO3 ferroelectric thin films

    International Nuclear Information System (INIS)

    Vendrell, X.; Raymond, O.; Ochoa, D.A.; García, J.E.; Mestres, L.

    2015-01-01

    Lead-free (K,Na)NbO 3 (KNN) and La doped (K,Na)NbO 3 (KNN-La) thin films are grown on SrTiO 3 substrates using the chemical solution deposition method. The effect of adding different amounts of Na and K excess (0–20 mol%) is investigated. The results confirm the necessity of adding 20 mol% excess amounts of Na and K precursor solutions in order to avoid the formation of the secondary phase, K 4 Nb 6 O 17 , as confirmed by X-ray diffraction and Raman spectroscopy. Moreover, when adding a 20 mol% of alkaline metal excess, the thin films are highly textured with out-of-plane preferential orientation in the [100] direction of the [100] orientation of the substrate. Doping with lanthanum results in a decrease of the leakage current density at low electric field, and an increase in the dielectric permittivity across the whole temperature range (80–380 K). Although the (100)-oriented KNN and KNN-La films exhibited rounded hysteresis loops, at low temperatures the films show the typical ferroelectric hysteresis loops. - Highlights: • (K 0.5 Na 0.5 )NbO 3 and [(K 0.5 Na 0.5 ) 0.985 La 0.005 ]NbO 3 thin films have been prepared. • The obtained thin films show an excellent (100) preferred orientation. • Doping with lanthanum results in a decrease of the leakage current density. • The dielectric properties are enhanced when doping with lanthanum

  11. The Enhanced Formaldehyde-Sensing Properties of P3HT-ZnO Hybrid Thin Film OTFT Sensor and Further Insight into Its Stability

    Directory of Open Access Journals (Sweden)

    Huiling Tai

    2015-01-01

    Full Text Available A thin-film transistor (TFT having an organic–inorganic hybrid thin film combines the advantage of TFT sensors and the enhanced sensing performance of hybrid materials. In this work, poly(3-hexylthiophene (P3HT-zinc oxide (ZnO nanoparticles’ hybrid thin film was fabricated by a spraying process as the active layer of TFT for the employment of a room temperature operated formaldehyde (HCHO gas sensor. The effects of ZnO nanoparticles on morphological and compositional features, electronic and HCHO-sensing properties of P3HT-ZnO thin film were systematically investigated. The results showed that P3HT-ZnO hybrid thin film sensor exhibited considerable improvement of sensing response (more than two times and reversibility compared to the pristine P3HT film sensor. An accumulation p-n heterojunction mechanism model was developed to understand the mechanism of enhanced sensing properties by incorporation of ZnO nanoparticles. X-ray photoelectron spectroscope (XPS and atomic force microscopy (AFM characterizations were used to investigate the stability of the sensor in-depth, which reveals the performance deterioration was due to the changes of element composition and the chemical state of hybrid thin film surface induced by light and oxygen. Our study demonstrated that P3HT-ZnO hybrid thin film TFT sensor is beneficial in the advancement of novel room temperature HCHO sensing technology.

  12. Piezoelectric MEMS: Ferroelectric thin films for MEMS applications

    Science.gov (United States)

    Kanno, Isaku

    2018-04-01

    In recent years, piezoelectric microelectromechanical systems (MEMS) have attracted attention as next-generation functional microdevices. Typical applications of piezoelectric MEMS are micropumps for inkjet heads or micro-gyrosensors, which are composed of piezoelectric Pb(Zr,Ti)O3 (PZT) thin films and have already been commercialized. In addition, piezoelectric vibration energy harvesters (PVEHs), which are regarded as one of the key devices for Internet of Things (IoT)-related technologies, are promising future applications of piezoelectric MEMS. Significant features of piezoelectric MEMS are their simple structure and high energy conversion efficiency between mechanical and electrical domains even on the microscale. The device performance strongly depends on the function of the piezoelectric thin films, especially on their transverse piezoelectric properties, indicating that the deposition of high-quality piezoelectric thin films is a crucial technology for piezoelectric MEMS. On the other hand, although the difficulty in measuring the precise piezoelectric coefficients of thin films is a serious obstacle in the research and development of piezoelectric thin films, a simple unimorph cantilever measurement method has been proposed to obtain precise values of the direct or converse transverse piezoelectric coefficient of thin films, and recently this method has become to be the standardized testing method. In this article, I will introduce fundamental technologies of piezoelectric thin films and related microdevices, especially focusing on the deposition of PZT thin films and evaluation methods for their transverse piezoelectric properties.

  13. Influence of the vacuum interface on the charge distribution in V2O3 thin films

    KAUST Repository

    Schwingenschlögl, Udo

    2009-09-22

    The electronic structure of V2O3 thin films is studied by means of the augmented spherical wave method as based on density functional theory and the local density approximation. We establish that the effects of charge redistribution, induced by the vacuum interface, in such films are restricted to a very narrow surface layer of ≈15 Å thickness. As a consequence, charge redistribution can be ruled out as a source of the extraordinary thickness dependence of the metal–insulator transition observed in V2O3 thin films of ~100–1000 Å thickness.

  14. A photoelectrochemical (PEC) study on graphene oxide based hematite thin films heterojunction (R-GO/Fe2O3)

    Science.gov (United States)

    Sharma, Poonam; Zachariah, Michael; Ehrman, Sheryl; Shrivastava, Rohit; Dass, Sahab; Satsangi, Vibha; Michael Zachariah, Sheryl Ehrman Collaboration; Rohit Shrivastava, Sahab Dass Collaboration; Vibha R Satsangi, Poonam Sharma Team

    2013-03-01

    Graphene has an excellent electronic conductivity, a high theoretical surface area of 2630 m2/g and excellent mechanical properties and, thus, is a promising component for high-performance electrode materials. Following this, GO has been used to modify the PEC response of photoactive material hematite thin films in PEC cell. A reduced graphene oxide/iron oxide (R-GO/Fe2O3) thin film structure has been successfully prepared on ITO by directly growing iron oxide particles on the thermally reduced graphene oxide sheets prepared from suspension of exfoliated graphene oxide. R-GO/Fe2O3 thin films were tested in PEC cell and offered ten times higher photocurrent density than pristine Fe2O3 thin film sample. XRD, SEM, EDS, UV-Vis, Mott-Schottky and Raman studies were carried out to study spectro-electrochemical properties. Enhanced PEC performance of these photoelectrodes was attributed to its porous morphology, improved conductivity upon favorable carrier transfer across the oxides interface.

  15. Pulsed laser deposited KY3F10: Ho3+ thin films: Influence of target to substrate

    CSIR Research Space (South Africa)

    Debelo, NG

    2017-04-01

    Full Text Available The influence of target to substrate distance (dts) on the structural, morphological and photoluminescence (PL) properties of commercially obtained KY3F10 : Ho3+ phosphor thin films prepared by pulsed laser deposition is investigated for dts values...

  16. Cation disorder and gas phase equilibrium in an YBa 2Cu 3O 7- x superconducting thin film

    Science.gov (United States)

    Shin, Dong Chan; Ki Park, Yong; Park, Jong-Chul; Kang, Suk-Joong L.; Yong Yoon, Duk

    1997-02-01

    YBa 2Cu 3O 7- x superconducting thin films have been grown by in situ off-axis rf sputtering with varying oxygen pressure, Ba/Y ratio in a target, and deposition temperature. With decreasing oxygen pressure, increasing Ba/Y ratio, increasing deposition temperature, the critical temperature of the thin films decreased and the c-axis length increased. The property change of films with the variation of deposition variables has been explained by a gas phase equilibrium of the oxidation reaction of Ba and Y. Applying Le Chatelier's principle to the oxidation reaction, we were able to predict the relation of deposition variables and the resultant properties of thin films; the prediction was in good agreement with the experimental results. From the relation between the three deposition variables and gas phase equilibrium, a 3-dimensional processing diagram was introduced. This diagram has shown that the optimum deposition condition of YBa 2Cu 3O 7- x thin films is not a fixed point but can be varied. The gas phase equilibrium can also be applied to the explanation of previous results that good quality films were obtained at low deposition temperature using active species, such as O, O 3, and O 2+.

  17. Double switching hysteresis loop in a single layer Fe3Pt alloy thin films

    International Nuclear Information System (INIS)

    Nahid, M.A.I.; Suzuki, Takao

    2008-01-01

    The Fe 3 Pt alloy thin films were epitaxially grown on MgO(100) substrate by e-beam evaporation. The films were partially ordered at the substrate deposition temperature above 350 deg. C. These partially ordered films exhibit very large biaxial magnetic anisotropy constant in the order of 10 5 J/m 3 and produce double switching in the hysteresis loops. The difference of the switching field of these films can be up to about 3 x 10 5 A/m by tuning the angle of the applied field with respect to the easy axes. This double switching behavior stems from the large biaxial magnetic anisotropy of the films

  18. Preparation and thermoelectric properties of RF co-sputtered CoSb{sub 3} skutteruddite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Aziz [University of Science and Technology, Daejeon (Korea, Republic of); Han, Seungwoo [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); University of Science and Technology, Daejeon (Korea, Republic of)

    2014-11-15

    Various skutterudites have been under investigation because of their potential application in thermoelectric materials and devices. These studies indicate that bulk materials with a skutterudite type structure show reasonable thermoelectric behaviors at elevated temperatures, which make them suitable for high-temperature thermoelectric applications. The results of thermoelectric-property measurements on skutterudite-phase CoSb{sub 3} thin films are presented in this study in order to extend the bulk material concept to micro-device applications by using thin film deposition technology. Thin films are deposited on oxidized silicon substrates by using the RF co-sputtering method. The film's composition is found to depend strongly on the deposition conditions. The temperature at which the deposited films transition from an amorphous state to a crystalline state has been reported to be about 153 .deg. C. Therefore, some experiments are performed with the substrate temperature kept at 200 .deg. C to obtain polycrystalline films. The crystal structure of the film is evaluated by using x-ray diffraction (XRD) measurements. Energy dispersive spectroscopy (EDS) is used to determine the film's composition whereas the surface morphology and the thickness are investigated and measured by using scanning electron microscopy (SEM). Finally, the thermoelectric properties, namely, the electrical resistivity and the Seebeck coefficient, are used to calculate the power factor of the deposited thin films and, their variations with temperature are measured. We report a maximum power factor of 0.41 mW/mK{sup 2} for the film deposited at a 200 .deg. C substrate temperature.

  19. Microstructure and electric characteristics of AETiO3 (AE=Mg, Ca, Sr doped CaCu3Ti4O12 thin films prepared by the sol–gel method

    Directory of Open Access Journals (Sweden)

    Dong Xu

    2015-10-01

    Full Text Available This paper focuses on the effects of alkline-earth metal titante AETiO3 (AE=Mg, Ca, Sr doping on the microstructure and electric characteristics of CaCu3Ti4O12 thin films prepared by the sol–gel method. The results showed that the grain size of CCTO thin films could be increased by MgTiO3 doping. The movement of the grain boundaries was impeded by the second phases of CaTiO3 and SrTiO3 concentrating at grain boundaries in CaTiO3 and SrTiO3 doped CCTO thin films. Rapid ascent of dielectric constant could be observed in 0.1Mg TiO3 doped CCTO thin films, which was almost as three times high as pure CCTO thin film and the descent of the dielectric loss at low frequency could also be observed. In addition, the nonlinear coefficient (α, threshold voltage (VT and leakage current (IL of AETiO3 doped CCTO thin films (AE=Mg, Ca, Sr showed different variation with the increasing content of the MgTiO3, CaTiO3 and SrTiO3.

  20. Effect of high energy ions on the electrical and morphological properties of Poly(3-Hexylthiophene) (P3HT) thin film

    Science.gov (United States)

    Sharma, Trupti; Singhal, R.; Vishnoi, R.; Sharma, G. D.; Biswas, S. K.

    2018-05-01

    The spin-coated thin films of Poly(3-Hexylthiophene) (P3HT) on the glass and Si (double side polished) substrates have been irradiated with 55 MeV Si+4 swift heavy ions (SHI) at fluences in the range from 1 × 1010 to 1 × 1012 ions/cm2. Structural modifications produced by energetic ions are observed by characterization of pristine and irradiated P3HT thin films. Different techniques like high-resolution X-ray diffraction (HR-XRD), micro-Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR) were used to analyze the structural changes in the material. A significant increase in crystallinity and room temperature electrical conductivity of P3HT film has been detected on exposure to the heavy ions. The observed increase in the electrical conductivity with increased fluences is explained in the light of improved ordering of polymer chains after irradiation. Mott's variable range hopping model has been used to explain the conduction mechanism in the material in the temperature range of 230-350 K. The modification in surface properties also observed using AFM analysis and contact angle measurement. It is observed that nature of the P3HT thin films remains hydrophobic after irradiation.

  1. Structural, compositional and optical properties of spin coated MoO3 thin film

    Science.gov (United States)

    Jain, Vishva; Shah, Dimple; Patel, K. D.; Zankat, Chetan

    2018-05-01

    The attraction towards the MoO3 thin film is due to its wide range of application base on its properties. Its application in the field of energy storage and conversion as a cathode material for rechargeable lithium ion battery, hole selective layer in solar cell and in pseudocapacitors makes it more attractive material. Taking in consideration, economical route and tailoring advantage of film formation we have used spin coating method for the synthesis of the film with Ammonium heptamolybdate (NH4)6Mo7O24 4H2O) and distilled water as the precursor and solvent respectively on the glass substrate. The method also provides the large area synthesis of the film which is beneficial for the commercial applications. The film was spin coated at 1600 rpm with 4 % weight per volume ratio. The film so formed was annealed at 300 °C for 3 hours. The structural investigation was done by the X-Ray diffraction technique which shows the thin film of polycrystalline type. The average crystallize size is about 50 nm. The composition of the film was studied with the help of EDAX. The optical properties were studied by the photoluminescence and UV Spectroscopy. The results from both the characterization are well matched with each other. Photoluminescence studies show band to band emission observed at 416 nm shown in the fig. 5. From UV spectroscopy, using transmission and absorption spectra we observed the band gap edge around 3 eV. This is in accordance with the photoluminescence result.

  2. Investigation of Electrical, Optical and GaS Sensing properties Sol-Gel Derived WO3 Thin Films

    International Nuclear Information System (INIS)

    Dumludag, F.

    2008-01-01

    Tungsten oxide (WO 3 ) is a wide band gap n-type semiconductor. Thin films of WO 3 are considerable interest because of their potential applications in electrochromic devices, and gas sensors. In this work, WO 3 thin films were deposited on IDT (Interdigital electrodes) by a sol-gel dipping process. Precursor solution was prepared by dissolving of tungstic acid in ammonia. We investigated d.c. and a.c. (40 Hz-100 KHz) electrical properties of the films in the temperature range of 293K and 473K in vacuum ambient (10 - 2 mbar). We observed frequency dependent conductivity behavior at high frequencies. Absorption spectra of the film showed that a maximum absorption occurred at 330 nm. We also investigated the response of the films to vapors of the volatile organic compounds (acetone, chloroform, toluene, ethanol, ammonia) and water vapor. The films showed no sensitivity to the test gases at room temperature. Concentration of the vapors were controlled by mass flowmeters. All the measurement system was computerized

  3. Phonon Drag in Thin Films, Cases of Bi2Te3 and ZnTe

    Science.gov (United States)

    Chi, Hang; Uher, Ctirad

    2014-03-01

    At low temperatures, in (semi-)conductors subjected to a thermal gradient, charge carriers (electrons and holes) are swept (dragged) by out-of-equilibrium phonons due to strong electron-phonon interaction, giving rise to a large contribution to the Seebeck coefficient called the phonon-drag effect. Such phenomenon was surprisingly observed in our recent transport study of highly mismatched alloys as potential thermoelectric materials: a significant phonon-drag thermopower reaching 1.5-2.5 mV/K was recorded for the first time in nitrogen-doped ZnTe epitaxial layers on GaAs (100). In thin films of Bi2Te3, we demonstrate a spectacular influence of substrate phonons on charge carriers. We show that one can control and tune the position and magnitude of the phonon-drag peak over a wide range of temperatures by depositing thin films on substrates with vastly different Debye temperatures. Our experiments also provide a way to study the nature of the phonon spectrum in thin films, which is rarely probed but clearly important for a complete understanding of thin film properties and the interplay of the substrate and films. This work is supported by the Center for Solar and Thermal Energy Conversion, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0000957.

  4. Measurement of thermal conductance of La0.7Sr0.3MnO3 thin films deposited on SrTiO3 and MgO substrates

    Science.gov (United States)

    Aryan, A.; Guillet, B.; Routoure, J. M.; Fur, C.; Langlois, P.; Méchin, L.

    2015-01-01

    We present measurements of the thermal conductance of thin-film-on-substrate structures that could serve as thin film uncooled bolometers. Studied samples were 75 nm thick epitaxial La0.7Sr0.3MnO3 thin films deposited on SrTiO3 (0 0 1) and MgO (0 0 1) substrates patterned in square geometries of areas ranging from 50 μm × 50 μm to 200 μm × 200 μm. The model allows estimating thermal boundary conductance values at the interface between film and substrate of 0.28 ± 0.08 × 106 W K-1 m-2 for LSMO/STO (0 0 1) and 5.8 ± 3.0 × 106 W K-1 m-2 for LSMO/MgO (0 0 1) from measurements performed in the static regime. Analytical expressions of thermal conductance and thermal capacitance versus modulation frequency are compared to measurements of the elevation temperature due to absorbed incoming optical power. The overall good agreement found between measurements and model finally provides the possibility to calculate the bolometric response of thin film bolometers, thus predicting their frequency response for various geometries.

  5. Ab Initio Calculations for the BaTiO3 (001) Surface Structure

    Institute of Scientific and Technical Information of China (English)

    XUE Xu-Yan; WANG Chun-Lei; ZHONG Wei-Lie

    2004-01-01

    @@ The ab initio method within the local density approximation is applied to calculate cubic BaTiO3 (001) surface relaxation and rumpling for two different terminations (BaO and TiO2). Our calculations demonstrate that cubic perovskite BaTiO3 crystals possess surface polarization, accompanied by the presence of the relevant electric field.We analyse their electronic structures (band structure, density of states and the electronic density redistribution with emphasis on the covalency effects). The results are also compared with that of the previous ab initio calculations. Considerable increases of Ti-O chemical bond covalency nearby the surface have been observed.The band gap reduces especially for the TiO2 termination.

  6. Thin film device applications

    CERN Document Server

    Kaur, Inderjeet

    1983-01-01

    Two-dimensional materials created ab initio by the process of condensation of atoms, molecules, or ions, called thin films, have unique properties significantly different from the corresponding bulk materials as a result of their physical dimensions, geometry, nonequilibrium microstructure, and metallurgy. Further, these characteristic features of thin films can be drasti­ cally modified and tailored to obtain the desired and required physical characteristics. These features form the basis of development of a host of extraordinary active and passive thin film device applications in the last two decades. On the one extreme, these applications are in the submicron dimensions in such areas as very large scale integration (VLSI), Josephson junction quantum interference devices, magnetic bubbles, and integrated optics. On the other extreme, large-area thin films are being used as selective coatings for solar thermal conversion, solar cells for photovoltaic conver­ sion, and protection and passivating layers. Ind...

  7. Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells

    Science.gov (United States)

    Wang, Lan; Lin, Xianzhong; Ennaoui, Ahmed; Wolf, Christian; Lux-Steiner, Martha Ch.; Klenk, Reiner

    2016-02-01

    We report a route to deposit In2S3 thin films from air-stable, low-cost molecular precursor inks for Cd-free buffer layers in chalcopyrite-based thin film solar cells. Different precursor compositions and processing conditions were studied to define a reproducible and robust process. By adjusting the ink properties, this method can be applied in different printing and coating techniques. Here we report on two techniques, namely spin-coating and inkjet printing. Active area efficiencies of 12.8% and 12.2% have been achieved for In2S3-buffered solar cells respectively, matching the performance of CdS-buffered cells prepared with the same batch of absorbers.

  8. Intermediate surface structure between step bunching and step flow in SrRuO3 thin film growth

    Science.gov (United States)

    Bertino, Giulia; Gura, Anna; Dawber, Matthew

    We performed a systematic study of SrRuO3 thin films grown on TiO2 terminated SrTiO3 substrates using off-axis magnetron sputtering. We investigated the step bunching formation and the evolution of the SRO film morphology by varying the step size of the substrate, the growth temperature and the film thickness. The thin films were characterized using Atomic Force Microscopy and X-Ray Diffraction. We identified single and multiple step bunching and step flow growth regimes as a function of the growth parameters. Also, we clearly observe a stronger influence of the step size of the substrate on the evolution of the SRO film surface with respect to the other growth parameters. Remarkably, we observe the formation of a smooth, regular and uniform ``fish skin'' structure at the transition between one regime and another. We believe that the fish skin structure results from the merging of 2D flat islands predicted by previous models. The direct observation of this transition structure allows us to better understand how and when step bunching develops in the growth of SrRuO3 thin films.

  9. Polarization enhancement and ferroelectric switching enabled by interacting magnetic structures in DyMnO3 thin films

    KAUST Repository

    Lu, Chengliang

    2013-12-02

    The mutual controls of ferroelectricity and magnetism are stepping towards practical applications proposed for quite a few promising devices in which multiferroic thin films are involved. Although ferroelectricity stemming from specific spiral spin ordering has been reported in highly distorted bulk perovskite manganites, the existence of magnetically induced ferroelectricity in the corresponding thin films remains an unresolved issue, which unfortunately halts this step. In this work, we report magnetically induced electric polarization and its remarkable response to magnetic field (an enhancement of ?800% upon a field of 2 Tesla at 2 K) in DyMnO3 thin films grown on Nb-SrTiO3 substrates. Accompanying with the large polarization enhancement, the ferroelectric coercivity corresponding to the magnetic chirality switching field is significantly increased. A picture based on coupled multicomponent magnetic structures is proposed to understand these features. Moreover, different magnetic anisotropy related to strain-suppressed GdFeO 3-type distortion and Jahn-Teller effect is identified in the films.

  10. Structural, morphological, gas sensing and photocatalytic characterization of MoO3 and WO3 thin films prepared by the thermal vacuum evaporation technique

    Science.gov (United States)

    Arfaoui, A.; Touihri, S.; Mhamdi, A.; Labidi, A.; Manoubi, T.

    2015-12-01

    Thin films of molybdenum trioxide and tungsten trioxide were deposited on glass substrates using a simplified thermal evaporation under vacuum method monitored by heat treatment in flowing oxygen at 500 °C for 1 h. The structural and morphological properties of the films were investigated using X-ray diffraction, Raman spectroscopy, atomic force microscopy and scanning electron microscopy. The X-ray diffraction analysis shows that the films of MoO3 and WO3 were well crystallized in orthorhombic and monoclinic phase respectively with the crystallites preferentially oriented toward (2 0 0) direction parallel a-axis for both samples. In literature, we have shown in previous papers that structural and surface morphology of metal thin films play an important role in the gas detection mechanism. In this article, we have studied the response evolution of MoO3 and WO3 thin films sensors ethanol versus time, working temperature and the concentration of the ethanol. It was found that these films had high sensitivity to ethanol, which made them as a good candidate for the ethanol sensor. Finally, the photocatalytic activity of the samples was evaluated with respect to the degradation reaction of a wastewater containing methylene blue (MB) under UV-visible light irradiation. The molybdenum trioxide exhibits a higher degradation rate than the tungsten trioxide thin films under similar experimental conditions.

  11. Biomimetic thin film synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Graff, G.L.; Campbell, A.A.; Gordon, N.R.

    1995-05-01

    The purpose of this program is to develop a new process for forming thin film coatings and to demonstrate that the biomimetic thin film technology developed at PNL is useful for industrial applications. In the biomimetic process, mineral deposition from aqueous solution is controlled by organic functional groups attached to the underlying substrate surface. The coatings process is simple, benign, inexpensive, energy efficient, and particularly suited for temperature sensitive substrate materials (such as polymers). In addition, biomimetic thin films can be deposited uniformly on complex shaped and porous substrates providing a unique capability over more traditional line-of-sight methods.

  12. Tuning of Transport and Magnetic Properties in Epitaxial LaMnO3Thin Films

    Directory of Open Access Journals (Sweden)

    J. Chen

    2014-01-01

    Full Text Available The effect of compressive strain on the transport and magnetic properties of epitaxial LaMnO3thin films has been investigated. It is found that the transport and magnetic properties of the LaMnO3thin films grown on the LaAlO3 substrates can be tuned by the compressive strain through varying film thickness. And the insulator-metal transition, charge/orbital ordering transition, and paramagnetic-ferromagnetic transition are suppressed by the compressive strain. Consequently, the related electronic and magnetic transition temperatures decrease with an increase in the compressive strain. The present results can be explained by the strain-controlled lattice deformation and the consequent orbital occupation. It indicates that the lattice degree of freedom is crucial for understanding the transport and magnetic properties of the strongly correlated LaMnO3+δ.

  13. Solution processible Cu{sub 2}SnS{sub 3} thin films for cost effective photovoltaics: Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Sandra, E-mail: dias.sandra123@gmail.com; Murali, Banavoth; Krupanidhi, S.B.

    2015-11-01

    Thin films of Cu{sub 2}SnS{sub 3} (CTS) were deposited by the facile solution processed sol–gel route followed by a low-temperature annealing. The Cu–Sn-thiourea complex formation was analysed using Fourier Transform Infrared spectrophotometer (FTIR). The various phase transformations and the deposition temperature range for the initial precursor solution was determined using Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC). X-Ray Diffraction (XRD) studies revealed the tetragonal phase formation of the CTS annealed films. Raman spectroscopy studies further confirmed the tetragonal phase formation and the absence of any deterioratory secondary phases. The morphological investigations and compositional analysis of the films were determined using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) respectively. Atomic Force Microscopy (AFM) was used to estimate the surface roughness of 1.3 nm. The absorption coefficient was found to be 10{sup 4} cm{sup −1} and bandgap 1.3 eV which qualifies CTS to be a potential candidate for photovoltaic applications. The refractive index, extinction coefficient and relative permittivity of the film were measured by Spectroscopic ellipsometry. Hall effect measurements, indicated the p type nature of the films with a hole concentration of 2 × 10{sup 18} cm{sup −3}, electrical conductivity of 9 S/cm and a hole mobility of 29 cm{sup 2}/V. The properties of CTS as deduced from the current study, present CTS as a potential absorber layer material for thin film solar cells. - Highlights: • Cu{sub 2}SnS{sub 3} thin films have been synthesized by spin coating of a precursor solution. • The Cu–Sn-thiourea complex precursor was analysed. • The structural, optical and electrical properties of the thin films were studied. • Totally 24 infra-red, 30 optical, 29 Raman and 30 hyper Raman modes are active. • Refractive index, extinction coefficient and relative

  14. Morphology, structure, and electrical properties of YBa2Cu3Ox thin films on tilted NdGaO3 substrates, deposited by DC-sputtering

    International Nuclear Information System (INIS)

    Mozhaev, Peter B.; Kotelyanskii, Iosif M.; Luzanov, Valery A.; Mozhaeva, Julia E.; Donchev, Todor; Mateev, Emil; Nurgaliev, Timur; Bdikin, Igor K.; Narymbetov, Bakhyt Zh.

    2005-01-01

    Thin YBa 2 Cu 3 O x (YBCO) films were deposited using DC-sputtering technique on NdGaO 3 substrates, tilted from (1 1 0) orientation by 0-26 deg . The structure and surface quality of the substrates were carefully characterized to obtain reliable results of thin films deposition. Structural, morphological and electrical properties of the YBCO thin films show three different ranges of inclination angle: vicinal, intermediate and high. In the vicinal range the properties of the film are generally the same as of the standard films deposited on (1 1 0) NdGaO 3 substrate. An increase of the inclination angle to the intermediate range results in a significant improvement of morphology and structural quality of the film. Best electrical parameters are measured for the films of the intermediate range also. Probable reason for such behavior is simultaneous and regular seeding of the film in the joints of facets on the substrate surface. Further increase of inclination angle leads to step bunching and oxygen out-diffusion, destroying both structural and electrical perfection of the tilted-axes YBCO film

  15. Effect of annealing time on morphological characteristics of Ba(Zr,Ti)O3 thin films

    International Nuclear Information System (INIS)

    Cavalcante, L.S.; Anicete-Santos, M.; Pontes, F.M.; Souza, I.A.; Santos, L.P.S.; Rosa, I.L.V.; Santos, M.R.M.C.; Santos-Junior, L.S.; Leite, E.R.; Longo, E.

    2007-01-01

    Ba(Zr 0.50 Ti 0.50 )O 3 thin films were prepared by the polymeric precursor method using the annealing low temperature of 300 o C for 8, 16, 24, 48, 96 and 192h in a furnace tube with oxygen atmosphere. The X-ray diffraction patterns revealed that the film annealed for 192 h presented some crystallographic planes (1bar 0bar 0) (1bar 1bar 0) and (2bar 0bar 0) in its crystalline lattice. Fourier transformed infrared presented the formation of metal-oxygen stretching at around 756cm -1 . The atomic force microscopy analysis presented the growth of granules in the Ba(Zr 0.50 Ti 0.50 )O 3 films annealed from 8 to 96h. The crystalline film annealed for 192h already presents grains in its perovskite structure. It evidenced a reduction in the thickness of the thin films with the increase of the annealing time

  16. Indium sulfide thin films as window layer in chemically deposited solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lugo-Loredo, S. [Universidad Autónoma de Nuevo León, UANL, Fac. de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria San Nicolás de Los Garza Nuevo León, C.P. 66451 (Mexico); Peña-Méndez, Y., E-mail: yolapm@gmail.com [Universidad Autónoma de Nuevo León, UANL, Fac. de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria San Nicolás de Los Garza Nuevo León, C.P. 66451 (Mexico); Calixto-Rodriguez, M. [Universidad Tecnológica Emiliano Zapata del Estado de Morelos, Av. Universidad Tecnológica No. 1, C.P. 62760 Emiliano Zapata, Morelos (Mexico); Messina-Fernández, S. [Universidad Autónoma de Nayarit, Ciudad de la Cultura “Amado Nervo” S/N, C.P. 63190 Tepic, Nayarit (Mexico); Alvarez-Gallegos, A. [Universidad Autónoma del Estado de Morelos, Centro de Investigación en Ingeniería y Ciencias Aplicadas, Av. Universidad 1001, C.P. 62209, Cuernavaca Morelos (Mexico); Vázquez-Dimas, A.; Hernández-García, T. [Universidad Autónoma de Nuevo León, UANL, Fac. de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria San Nicolás de Los Garza Nuevo León, C.P. 66451 (Mexico)

    2014-01-01

    Indium sulfide (In{sub 2}S{sub 3}) thin films have been synthesized by chemical bath deposition technique onto glass substrates using In(NO{sub 3}){sub 3} as indium precursor and thioacetamide as sulfur source. X-ray diffraction studies have shown that the crystalline state of the as-prepared and the annealed films is β-In{sub 2}S{sub 3}. Optical band gap values between 2.27 and 2.41 eV were obtained for these films. The In{sub 2}S{sub 3} thin films are photosensitive with an electrical conductivity value in the range of 10{sup −3}–10{sup −7} (Ω cm){sup −1}, depending on the film preparation conditions. We have demonstrated that the In{sub 2}S{sub 3} thin films obtained in this work are suitable candidates to be used as window layer in thin film solar cells. These films were integrated in SnO{sub 2}:F/In{sub 2}S{sub 3}/Sb{sub 2}S{sub 3}/PbS/C–Ag solar cell structures, which showed an open circuit voltage of 630 mV and a short circuit current density of 0.6 mA/cm{sup 2}. - Highlights: • In{sub 2}S{sub 3} thin films were deposited using the Chemical Bath Deposition technique. • A direct energy band gap between 2.41 to 2.27 eV was evaluated for the In{sub 2}S{sub 3} films. • We made chemically deposited solar cells using the In{sub 2}S{sub 3} thin films.

  17. Effect of preparation conditions on the properties of Cu3BiS3 thin films grown by a two - step process

    Science.gov (United States)

    Mesa, F.; Gordillo, G.

    2009-05-01

    Cu3BiS3 thin films were prepared on soda-lime glass substrates by co-evaporation of the precursors in a two-step process; for that, the metallic precursors were evaporated from a tungsten boat in presence of elemental sulfur evaporated from a tantalum effusion cell. The films were characterized by spectral transmittance, atomic force microscopy AFM and x-ray diffraction (XRD) measurements to investigate the effect of the growth conditions on the optical, morphological and structural properties. The results revealed that, independently of the deposition conditions, the films grow only in the orthorhombic Cu3BiS3 phase. It was also found that the Cu3BiS3 films present p-type conductivity, a high absorption coefficient (greater than 104 cm-1) and an energy band gap Eg of about 1.41 eV, indicating that this compound has good properties to perform as absorbent layer in thin film solar cells.

  18. Preparation and characterization of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) composite thin films highly loaded with platinum nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chao-Ching, E-mail: ccchang@tku.edu.tw [Department of Chemical and Materials Engineering, Tamkang University, No. 151, Yingzhuan Rd., Danshui Dist., New Taipei City 25137, Taiwan (China); Energy and Opto-Electronic Materials Research Center, Tamkang University, No. 151, Yingzhuan Rd., Danshui Dist., New Taipei City 25137, Taiwan (China); Jiang, Ming-Tai [Department of Chemical and Materials Engineering, Tamkang University, No. 151, Yingzhuan Rd., Danshui Dist., New Taipei City 25137, Taiwan (China); Chang, Chen-Liang; Lin, Cheng-Lan [Department of Chemical and Materials Engineering, Tamkang University, No. 151, Yingzhuan Rd., Danshui Dist., New Taipei City 25137, Taiwan (China); Energy and Opto-Electronic Materials Research Center, Tamkang University, No. 151, Yingzhuan Rd., Danshui Dist., New Taipei City 25137, Taiwan (China)

    2011-06-15

    Research highlights: {yields} Nano-sized and mono-dispersed Pt nanoparticles were synthesized by a polyol method. {yields} A thin film of PEDOT:PSS loaded with high concentration of Pt nanoparticles has been prepared. {yields} The PEDOT:PSS-Pt modified electrode has good potential to serve as a counter electrode in DSSC. - Abstract: In this work, we propose a simple and efficient, low-temperature ({approx}120 deg. C) process to prepare transparent thin films of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) loaded with high concentration (up to 22.5 wt%) of platinum (Pt) nanoparticles. Firstly, an improved polyol method was modified to synthesize nano-sized ({approx}5 nm) and mono-dispersed Pt particles. These nanoparticles were incorporated into the matrix of PEDOT:PSS thin films via a spin coating/drying procedure. The electrochemical activities of the PEDOT:PSS thin film modified electrodes with respect to the I{sup -}/I{sub 3}{sup -} redox reactions were investigated. It was found that the modified electrode of PEDOT:PSS thin film containing 22.5 wt% Pt exhibited the electrochemical activity comparable to the conventional Pt thin film electrode, suggesting that this electrode has good potential to serve as a counter electrode in dye-sensitized solar cells.

  19. Analysis of multiferroic properties in BiMnO3 thin films

    International Nuclear Information System (INIS)

    Grizalez, M; Mendoza, G A; Prieto, P

    2009-01-01

    Textured BiMnO 3 [111] thin films on SrTiO 3 (100) and Pt/TiO 2 /SiO 2 substrates were grown via r.f. magnetron sputtering (13.56 MHz). The XRD spectra confirmed a monoclinic structure and high-quality textured films for the BiMnO 3 films. The films grown on SrTiO 3 (100) showed higher crystalline quality than those developed on Pt/TiO 2 /SiO 2 . Through optimized oxygen pressure of 5x10 -2 mbar during the r.f. sputtering deposition, the crystalline orientation of the BiMnO 3 film was improved with respect to the previously reported value of 2x10 -1 mbar. The values of spontaneous polarization (P s ), remnant polarization (P r ), and coercive field (F c ) from ferroelectric hysteresis loops (P-E) at different temperatures were also obtained. Samples with higher crystalline order revealed better dielectric properties (high P s and P r values and a low F c ). For films on both types of substrates, the ferroelectric behavior was found to persist up to 400K. Measurements at higher temperatures were difficult to obtain given the increased conductivity of the films. Magnetic hysteresis loops from 5K to 120K were obtained for BiMnO 3 films grown on SrTiO 3 and Pt/TiO 2 /SiO 2 substrates. The results suggested that the coexistence of the magnetic and electric phases persists up to 120K.

  20. Hall effect of K-doped superconducting thin films

    Energy Technology Data Exchange (ETDEWEB)

    Son, Eunseon; Lee, Nam Hoon; Kang, Won Nam [Dept. of physics, Sungkyunkwan University, Suwon (Korea, Republic of); Hwang, Tae Jong; Kim, Dong Ho [Dept. of physics, Yeungnam University, Gyeongsan(Korea, Republic of)

    2013-09-15

    We have studied Hall effect for potassium (K)-doped BaFe{sub 2}As{sub 2}superconducting thin films by analyzing the relation between the longitudinal resistivity (ρ{sub xy}) and the Hall resistivity (ρ{sub xy}). The thin films used in this study were fabricated on Al{sub O3} (000l) substrates by using an ex-situ pulsed laser deposition (PLD) technique under a high-vacuum condition of ∼10{sup -6} Torr. The samples showed the high superconducting transition temperatures (T{sub C}) of ∼40 K. The ρ{sub xx} and ρ{sub xy}the for K-doped BaFeAs{sub 2} thin films were measured by using a physical property measurement system (PPMS) with a temperature sweep (T-sweep) mode at an applied current density of 100 A/cm{sup 2} and at magnetic fields from 0 up to 9 T. We report the T-sweep results of the ρ{sub xx} and the ρ{sub xy} to investigate Hall scaling behavior on the basis of the relation of ρ{sub xy} = A(ρ{sub xy}){sup β}. The ρ{sub xx} values are 3.0 ± 0.2 in the c-axis-oriented K-doped BaFeAs{sub 2} thin films, whereas the thin films with various oriented-directions like a polycrystal showed slightly lower β than that of c-axis-oriented thin films. Interestingly, the β value is decreased with increasing magnetic fields.

  1. YBa2Cu3O(7-x) based superconducting thin films by multitarget sputtering

    International Nuclear Information System (INIS)

    Bouteloup, E.; Mercey, B.; Poullain, G.; Brousse, T.; Murray, H.; Raveau, B.

    1990-01-01

    This paper reports a new technique to prepare superconducting YBa 2 Cu 3 O (7-x) thin films. The multitarget sputtering apparatus described below allows the simultaneous and reproducible production of numerous films with a metallic composition close to Y 17% Ba 33% Cu 50% . Superconducting films (R = 0) at 80 K have been produced on polycrystalline zirconia substrates after a high temperature annealing [fr

  2. Ultrafast Magnetization Dynamics of SrRuO3 Thin Films

    International Nuclear Information System (INIS)

    Langner, Matthew C.

    2009-01-01

    Itinerant ferromagnet SrRuO3 has drawn interest from physicists due to its unusual transport and magnetic properties as well as from engineers due to its low resistivity and good lattice-matching to other oxide materials. The exact electronic structure remains a mystery, as well as details of the interactions between magnetic and electron transport properties. This thesis describes the use of time-resolved magneto-optical Kerr spectroscopy to study the ferromagnetic resonance of SrRuO3 thin films, where the ferromagnetic resonance is initiated by a sudden change in the easy axis direction in response to a pump pulse. The rotation of the easy axis is induced by laser heating, taking advantage of a temperature-dependent easy axis direction in SrRuO3 thin films. By measuring the change in temperature of the magnetic system in response to the laser pulse, we find that the specific heat is dominated by magnons up to unusually high temperature, ∼ 100 K, and thermal diffusion is limited by a boundary resistance between the film and the substrate that is not consistent with standard phonon reflection and scattering models. We observe a high FMR frequency, 250 GHz, and large Gilbert damping parameter, alpha ∼ 1, consistent with strong spin-orbit coupling. We observe a time-dependent change in the easy axis direction on a ps time-scale, and we find that parameters associated with the change in easy axis, as well as the damping parameter, have a non-monotonic temperature dependence similar to that observed in anomalous Hall measurements.

  3. Fabrication and characterization of In2S3 thin films deposited by thermal evaporation technique

    International Nuclear Information System (INIS)

    Timoumi, A.; Bouzouita, H.; Kanzari, M.; Rezig, B.

    2005-01-01

    Indium sulphide, In 2 S 3 , thin films present an alternative to conventional CdS films as buffer layer for CIS-based thin film solar cells. The objective is to eliminate toxic cadmium for environmental reasons. Indium sulphide is synthesized and deposited by single source vacuum thermal evaporation method on glass substrates. The films are analyzed by X-ray diffraction (XRD) and spectrophotometric measurements. They have a good crystallinity, homogeneity and adhesion. The X-ray diffraction analysis confirmed the initial amorphous nature of the deposited InS film and phase transition into crystalline In 2 S 3 formed upon annealing at free air for 250 deg. C substrate temperature for 2 h. The optical constants of the deposited films were obtained from the analysis of the experimental recorded transmission and reflectance spectral data over the wavelength range of 300-1800 nm. We note that the films annealed at 250 deg. C for 2 h show a good homogeneity with 80% transmission. An analysis of the optical absorption data of the deposited films revealed an optical direct band gap energy in the range of 2.0-2.2 eV

  4. Molecular dynamics simulation of Cu/Au thin films under temperature gradient

    International Nuclear Information System (INIS)

    Li, Qibin; Peng, Xianghe; Peng, Tiefeng; Tang, Qizhong; Zhang, Xiaomin; Huang, Cheng

    2015-01-01

    Graphical abstract: Heat transportation in the thin films. - Highlights: • The coherent lattice interface is found at thin films after annealing. • The vacancies are observed clearly in the deposit thin films. • The defect and component will influence the energy transportation in the coatings. • The vacancies and lattice mismatch can enlarge the mobility of atoms. • The phonon transportation in thin films has no apparent rule. - Abstract: Three modulation period thin films, 1.8 nm Cu/3.6 nm Au, 2.7 nm Cu/2.7 nm Au and 3.6 nm Cu/1.8 nm Au, are obtained from deposition method and ideal modeling based on lattice constant, to examine their structures and thermophysical characteristics under temperature gradient. The coherent lattice interface is found both at deposit and ideal thin films after annealing. Also, the vacancies are observed clearly in the deposit thin films. The defect and component of thin films will influence the energy transportation in the coatings. The vacancies and lattice mismatch can enlarge the mobility of atoms and result in the failure of coating under the thermal stress. The power spectrum of atoms’ movement has no apparent rule for phonon transportation in thin films. The results are helpful to reveal the micro-mechanism and provide reasonable basis for the failure of metallic coatings.

  5. Molecular dynamics simulation of Cu/Au thin films under temperature gradient

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qibin, E-mail: qibinli@cqu.edu.cn [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030 (China); Chongqing Key Laboratory of Heterogeneous Material Mechanics, Chongqing University, Chongqing 400030 (China); Peng, Xianghe [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030 (China); Peng, Tiefeng, E-mail: pengtiefeng@cqu.edu.cn [State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030 (China); Tang, Qizhong [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); Zhang, Xiaomin [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); Chongqing Key Laboratory of Heterogeneous Material Mechanics, Chongqing University, Chongqing 400030 (China); Huang, Cheng [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China)

    2015-12-01

    Graphical abstract: Heat transportation in the thin films. - Highlights: • The coherent lattice interface is found at thin films after annealing. • The vacancies are observed clearly in the deposit thin films. • The defect and component will influence the energy transportation in the coatings. • The vacancies and lattice mismatch can enlarge the mobility of atoms. • The phonon transportation in thin films has no apparent rule. - Abstract: Three modulation period thin films, 1.8 nm Cu/3.6 nm Au, 2.7 nm Cu/2.7 nm Au and 3.6 nm Cu/1.8 nm Au, are obtained from deposition method and ideal modeling based on lattice constant, to examine their structures and thermophysical characteristics under temperature gradient. The coherent lattice interface is found both at deposit and ideal thin films after annealing. Also, the vacancies are observed clearly in the deposit thin films. The defect and component of thin films will influence the energy transportation in the coatings. The vacancies and lattice mismatch can enlarge the mobility of atoms and result in the failure of coating under the thermal stress. The power spectrum of atoms’ movement has no apparent rule for phonon transportation in thin films. The results are helpful to reveal the micro-mechanism and provide reasonable basis for the failure of metallic coatings.

  6. Persistent semi-metal-like nature of epitaxial perovskite CaIrO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Abhijit; Jeong, Yoon Hee, E-mail: yhj@postech.ac.kr [Department of Physics, POSTECH, Pohang 790-784 (Korea, Republic of)

    2015-05-21

    Strong spin-orbit coupled 5d transition metal based ABO{sub 3} oxides, especially iridates, allow tuning parameters in the phase diagram and may demonstrate important functionalities, for example, by means of strain effects and symmetry-breaking, because of the interplay between the Coulomb interactions and strong spin-orbit coupling. Here, we have epitaxially stabilized high quality thin films of perovskite (Pv) CaIrO{sub 3}. Film on the best lattice-matched substrate shows semi-metal-like characteristics. Intriguingly, imposing tensile or compressive strain on the film by altering the underlying lattice-mismatched substrates still maintains semi-metallicity with minute modification of the effective correlation as tensile (compressive) strain results in tiny increases (decreases) of the electronic bandwidth. In addition, magnetoresistance remains positive with a quadratic field dependence. This persistent semi-metal-like nature of Pv-CaIrO{sub 3} thin films with minute changes in the effective correlation by strain may provide new wisdom into strong spin-orbit coupled 5d based oxide physics.

  7. Pulsed laser deposited Al-doped ZnO thin films for optical applications

    Directory of Open Access Journals (Sweden)

    Gurpreet Kaur

    2015-02-01

    Full Text Available Highly transparent and conducting Al-doped ZnO (Al:ZnO thin films were grown on glass substrates using pulsed laser deposition technique. The profound effect of film thickness on the structural, optical and electrical properties of Al:ZnO thin films was observed. The X-ray diffraction depicts c-axis, plane (002 oriented thin films with hexagonal wurtzite crystal structure. Al-doping in ZnO introduces a compressive stress in the films which increase with the film thickness. AFM images reveal the columnar grain formation with low surface roughness. The versatile optical properties of Al:ZnO thin films are important for applications such as transparent electromagnetic interference (EMI shielding materials and solar cells. The obtained optical band gap (3.2–3.08 eV was found to be less than pure ZnO (3.37 eV films. The lowering in the band gap in Al:ZnO thin films could be attributed to band edge bending phenomena. The photoluminescence spectra gives sharp visible emission peaks, enables Al:ZnO thin films for light emitting devices (LEDs applications. The current–voltage (I–V measurements show the ohmic behavior of the films with resistivity (ρ~10−3 Ω cm.

  8. Thin Film Photovoltaic Partnership Project | Photovoltaic Research | NREL

    Science.gov (United States)

    Thin Film Photovoltaic Partnership Project Thin Film Photovoltaic Partnership Project NREL's Thin Film Photovoltaic (PV) Partnership Project led R&D on emerging thin-film solar technologies in the United States from 1994 to 2009. The project made many advances in thin-film PV technologies that allowed

  9. Ga2O3-In2O3 thin films on sapphire substrates: Synthesis and ultraviolet photoconductivity

    Science.gov (United States)

    Muslimov, A. E.; Butashin, A. V.; Kolymagin, A. B.; Nabatov, B. V.; Kanevsky, V. M.

    2017-11-01

    The structure and electrical and optical properties of β-Ga2O3-In2O3 thin films on sapphire substrates with different orientations have been investigated. The samples have been prepared by annealing of gallium-indium metallic films on sapphire substrates in air at different gallium-to-indium ratios in the initial mixture. The photoconductivity of these structures in the solar-blind ultraviolet spectral region has been examined.

  10. Thin Film & Deposition Systems (Windows)

    Data.gov (United States)

    Federal Laboratory Consortium — Coating Lab: Contains chambers for growing thin film window coatings. Plasma Applications Coating Lab: Contains chambers for growing thin film window coatings. Solar...

  11. Antimicrobial effect of Al2O3, Ag and Al2O3/Ag thin films on Escherichia coli and Pseudomonas putida

    International Nuclear Information System (INIS)

    Angelov, O; Stoyanova, D; Ivanova, I; Todorova, S

    2016-01-01

    The influence of Al 2 O 3 , Ag and Al 2 O 3 /Ag thin films on bacterial growth of Gramnegative bacteria Pseudomonas putida and Escherichia coli is studied. The nanostructured thin films are deposited on glass substrates without intentional heating through r.f. magnetron sputtering in Ar atmosphere of Al 2 O 3 and Ag targets or through sequential sputtering of Al 2 O 3 and Ag targets, respectively. The individual Ag thin films (thickness 8 nm) have a weak bacteriostatic effect on Escherichia coli expressed as an extended adaptive phase of the bacteria up to 5 hours from the beginning of the experiment, but the final effect is only 10 times lower bacterial density than in the control. The individual Al 2 O 3 film (20 nm) has no antibacterial effect against two strains E. coli - industrial and pathogenic. The Al 2 O 3 /Ag bilayer films (Al 2 O 3 20 nm/Ag 8 nm) have strong bactericidal effect on Pseudomonas putida and demonstrate an effective time of disinfection for 2 hours. The individual films Al2O3 and Ag have not pronounced antibacterial effect on Pseudomonas putida . A synergistic effect of Al2O3/Ag bilayer films in formation of oxidative species on the surface in contact with the bacterial suspension could be a reason for their antimicrobial effect on E. coli and P. putida . (paper)

  12. Characterization of the insulator barrier and the superconducting transition temperature in GdBa2Cu3O7−δ/BaTiO3 bilayers for application in tunnel junctions

    International Nuclear Information System (INIS)

    Navarro, H.; Sirena, M.; Haberkorn, N.; Yang, Ilkyu; Kim, Jeehoon

    2015-01-01

    The optimization of the superconducting properties in a bottom electrode and the quality of an insulator barrier are the first steps in the development of superconductor/insulator/superconductor tunnel junctions. Here, we study the quality of a BaTiO 3 tunnel barrier deposited on a 16 nm thick GdBa 2 Cu 3 O 7−δ thin film by using conductive atomic force microscopy. We find that the tunnel current is systematically reduced (for equal applied voltage) by increasing the BaTiO 3 barrier thickness between 1.6 and 4 nm. The BaTiO 3 layers present an energy barrier of ≈1.2 eV and an attenuation length of 0.35–0.5 nm (depending on the applied voltage). The GdBa 2 Cu 3 O 7−δ electrode is totally covered by a BaTiO 3 thickness above 3 nm. The presence of ferroelectricity was verified by piezoresponse force microscopy for a 4 nm thick BaTiO 3 top layer. The superconducting transition temperature of the bilayers is systematically suppressed by increasing the BaTiO 3 thickness. This fact can be associated with stress at the interface and a reduction of the orthorhombicity of the GdBa 2 Cu 3 O 7−δ . The reduction in the orthorhombicity is expected by considering the interface mismatch and it can also be affected by reduced oxygen stoichiometry (poor oxygen diffusion across the BaTiO 3 barrier)

  13. Nanoscale Control of Exchange Bias with BiFeO3 Thin Films

    NARCIS (Netherlands)

    Martin, Lane W.; Chu, Ying-Hao; Holcomb, Mikel B.; Huijben, Mark; Yu, Pu; Han, Shu-Jen; Lee, Donkoun; Wang, Shan X.; Ramesh, R.

    2008-01-01

    We demonstrate a direct correlation between the domain structure of multiferroic BiFeO3 thin films and exchange bias of Co0.9Fe0.1/BiFeO3 heterostructures. Two distinct types of interactions − an enhancement of the coercive field (exchange enhancement) and an enhancement of the coercive field

  14. Purely hopping conduction in c-axis oriented LiNbO3 thin films

    Science.gov (United States)

    Shandilya, Swati; Tomar, Monika; Sreenivas, K.; Gupta, Vinay

    2009-05-01

    Dielectric constant and ac conductivity of highly c-axis oriented LiNbO3 thin film grown by pulsed laser deposition were studied in a metal-insulator-metal configuration over a wide temperature (200 to 450 K) and frequency (100 Hz to 1 MHz) range. The preferred oriented Al (1%) doped ZnO film with electrical conductivity 1.1×103 Ω-1 cm-1 was deposited for dual purpose: (1) to serve as nucleating center for LiNbO3 crystallites along preferred c-axis growth direction, and (2) to act as a suitable bottom electrode for electrical studies. The room temperature dc conductivity (σdc) of LiNbO3 film was about 5.34×10-10 Ω-1 cm-1 with activation energy ˜0.3 eV, indicating extrinsic conduction. The ac conductivity σac was found to be much higher in comparison to σdc in the low temperature region (300 K), σac shows a weak frequency dependence, whereas dielectric constant exhibits a strong frequency dispersion. The dielectric dispersion data has been discussed in the light of theoretical models based on Debye type mixed conduction and purely hopping conduction. The dominant conduction in c-axis oriented LiNbO3 thin film is attributed to the purely hopping where both σdc and σac arise due to same mechanism.

  15. Ajuste teórico de las curvas PTCR de BaTiO3 dopado con niobio

    Directory of Open Access Journals (Sweden)

    Castro, M. S.

    2002-02-01

    Full Text Available In this work, a theoretical fitting to the experimental PTCR effect in slightly Nb-doped BaTiO3 from the Heywang-Jonker model is simulated. Besides, a qualitative approach was used to evaluate the GBBL characteristics of strongly Nb - doped BaTiO3. In both cases, a link between the electrical properties and the defect profile developed in these based - BaTiO3 ceramics was established. From the results, good agreement between experimental and calculated results was obtained for the PTCR ceramics. Asmall increment in Nb2O5 concentration leads to an increasing in the concentration of occupied acceptor states, the energy of the surface state and also the barrier height. In these cases, microstructural observations shown an important grain growth with average grain size between 10 and 100μm. EPR results clearly indicate low concentration of cationic vacancies for these materials. This phenomenon is associated to a charge-compensation mechanism in slightly-doped BaTiO3, that result in a semiconducting behaviour. On the other hand, the electrical behaviour of strongly–doped BaTiO3 moves away from the PTCR effect, and the material becomes insulating with noticeable GBBL characteristics. In this case, microstructural observations along defect structure analysis encourage the hypothesis in which barium vacancies act as acceptor at grain boundaries and play and important role in restricting grain growth of Nb2O5-BaTiO3 ceramics.En este trabajo se determinó la influencia de la concentración de Nb2O5 sobre el comportamiento PTCR de cerámicos basados en BaTiO3. Por otra parte, se estudió el impacto de una gran concentración del dopante sobre el comportamiento GBBL del BaTiO3. En ambos casos, se estableció una relación entre las propiedades eléctricas observadas y la estructura de defectos iónicos desarrollada. La aplicación del modelo de Heywang-Jonker permite el ajuste teórico de las curvas de resistividad – temperatura de los cerámicos PTCR

  16. A theoretical investigation of the influence of the surface effect on the ferroelectric property of strained barium titanate film

    Science.gov (United States)

    Fang, Chao; Liu, Wei Hua

    2017-07-01

    The influence of the surface effect on the ferroelectric property of strained barium titanate film has been investigated. In this study, based on time-dependent Ginsburg-Landau-Devonshire thermodynamic theory, the surface effects have been simulated by introducing a surface constant, which leads to the strained BaTiO3 film consisting of inner tetragonal core and gradient lattice strain layer. Further, surface effects produce a depolarization field which has a dominant effect on the ferroelectric properties of the films. The spontaneous polarization, dielectric properties and ferroelectric hysteresis loop of BaTiO3 film are calculated under different boundary conditions. Theoretical and experimental results for strained BaTiO3 film are compared and discussed.

  17. Effect of precursor concentration on physical properties of nebulized spray deposited In2S3 thin films

    Directory of Open Access Journals (Sweden)

    J. Raj Mohamed

    2016-09-01

    Full Text Available The present work investigates the effect of precursor concentration (mc on the structural, optical, morphological and electrical conductivity properties of In2S3 thin films grown on amorphous glass substrates by nebulized spray pyrolysis (NSP technique. The mixed phase of cubic and tetragonal structure of In2S3 thin films at higher concentration has been observed by X-ray diffraction pattern. The reduced strain by increasing the precursor concentration increased the average crystallite from 17.8 to 28.9 nm. The energy dispersive analysis by X-ray (EDAX studies confirmed the presence of In and S. The transmittance, optical direct band gap energy, Urbach energy and skin depth of In2S3 films have been analyzed by optical absorption spectra. The better conductivity and mobility noticed at mc = 0.15 M are explained by carrier concentration and crystallite. Better optical and electrical conductivity behaviour of In2S3 thin film sample proposes for effective solar cell fabrication.

  18. Structure-property relations in sputter deposited epitaxial (1-x)Pb(Mg1/3Nb2/3)O3- xPbTiO3 thin films

    Science.gov (United States)

    Frederick, Joshua C.

    Lead-based ferroelectric materials are of significant technological importance for sensing and actuation due to their high piezoelectric performance (i.e., the ability to convert an electrical signal to mechanical displacement, and vice versa). Traditionally, bulk ceramic or single crystals materials have filled these roles; however, emerging technologies stand to benefit by incorporating thin films to achieve miniaturization while maintaining high efficiency and sensitivity. Currently, chemical systems that have been well characterized in bulk form (e.g. Pb(Mg1/3Nb2/3)O3- xPbTiO3, or PMN-xPT) require further study to optimize both the chemistry and structure for deployment in thin film devices. Furthermore, the effect of internal electric fields is more significant at the length scales of thin films, resulting in self biases that require compensation to reveal their intrinsic dielectric response. To this end, the structure-property relations of epitaxial PMN-xPT films sputter deposited on a variety of substrates were investigated. Attention was paid to how the structure (i.e., strain state, crystal structure, domain configuration, and defects) gave rise to the ferroelectric, dielectric, and piezoelectric response. Three-dimensional visualization of the dielectric response as a simultaneous function of electric field and temperature revealed the true phase transition of the films, which was found to correspond to the strain state and defect concentration. A lead-buffered anneal process was implemented to enhance the ferroelectric and dielectric response of the films without altering their stoichiometry. It was discovered that PMN- xPT films could be domain-engineered to exhibit a mixed domain state through chemistry and substrate choice. Such films exhibited a monoclinic distortion similar to that of the bulk compositions near the morphotropic phase boundary. Finally, it was revealed that the piezoelectric response could be greatly enhanced by declamping the film

  19. Valence control of cobalt oxide thin films by annealing atmosphere

    International Nuclear Information System (INIS)

    Wang Shijing; Zhang Boping; Zhao Cuihua; Li Songjie; Zhang Meixia; Yan Liping

    2011-01-01

    The cobalt oxide (CoO and Co 3 O 4 ) thin films were successfully prepared using a spin-coating technique by a chemical solution method with CH 3 OCH 2 CH 2 OH and Co(NO 3 ) 2 .6H 2 O as starting materials. The grayish cobalt oxide films had uniform crystalline grains with less than 50 nm in diameter. The phase structure is able to tailor by controlling the annealing atmosphere and temperature, in which Co 3 O 4 thin film was obtained by annealing in air at 300-600, and N 2 at 300, and transferred to CoO thin film by raising annealing temperature in N 2 . The fitted X-ray photoelectron spectroscopy (XPS) spectra of the Co2p electrons are distinguishable from different valence states of cobalt oxide especially for their satellite structure. The valence control of cobalt oxide thin films by annealing atmosphere contributes to the tailored optical absorption property.

  20. Characterization of organic thin films

    CERN Document Server

    Ulman, Abraham; Evans, Charles A

    2009-01-01

    Thin films based upon organic materials are at the heart of much of the revolution in modern technology, from advanced electronics, to optics to sensors to biomedical engineering. This volume in the Materials Characterization series introduces the major common types of analysis used in characterizing of thin films and the various appropriate characterization technologies for each. Materials such as Langmuir-Blodgett films and self-assembled monolayers are first introduced, followed by analysis of surface properties and the various characterization technologies used for such. Readers will find detailed information on: -Various spectroscopic approaches to characterization of organic thin films, including infrared spectroscopy and Raman spectroscopy -X-Ray diffraction techniques, High Resolution EELS studies, and X-Ray Photoelectron Spectroscopy -Concise Summaries of major characterization technologies for organic thin films, including Auger Electron Spectroscopy, Dynamic Secondary Ion Mass Spectrometry, and Tra...

  1. Piezoelectric characterization of Pb(Zr,Ti)O3 thin films deposited on metal foil substrates by dip coating

    Science.gov (United States)

    Hida, Hirotaka; Hamamura, Tomohiro; Nishi, Takahito; Tan, Goon; Umegaki, Toshihito; Kanno, Isaku

    2017-10-01

    We fabricated the piezoelectric bimorphs composed of Pb(Zr,Ti)O3 (PZT) thin films on metal foil substrates. To efficiently inexpensively manufacture piezoelectric bimorphs with high flexibility, 1.2-µm-thick PZT thin films were directly deposited on both surfaces of 10- and 20-µm-thick bare stainless-steel (SS) foil substrates by dip coating with a sol-gel solution. We confirmed that the PZT thin films deposited on the SS foil substrates at 500 °C or above have polycrystalline perovskite structures and the measured relative dielectric constant and dielectric loss were 323-420 and 0.12-0.17, respectively. The PZT bimorphs were demonstrated by comparing the displacements of the cantilever specimens driven by single- and double-side PZT thin films on the SS foil substrates under the same applied voltage. We characterized the piezoelectric properties of the PZT bimorphs and the calculated their piezoelectric coefficient |e 31,f| to be 0.3-0.7 C/m2.

  2. Preparation of Pb(Zr, Ti)O3 Thin Films on Glass Substrates

    Science.gov (United States)

    Hioki, Tsuyoshi; Akiyama, Masahiko; Ueda, Tomomasa; Onozuka, Yutaka; Hara, Yujiro; Suzuki, Kouji

    2000-09-01

    Lead-zirconate-titanate (PZT) thin films were prepared on non-alkaline glass substrates widely used in liquid crystal display (LCD) devices, by plasma-assisted magnetron RF sputtering with an immersed coil. After preparation of the PZT thin film, the glass was available for use in LCD device processing. No mutual diffusion of the elements was recognized between the glass substrate and the bottom electrode. The PZT layer had a dense film structure with rectangular and columnar grains, and only its perovskite phase was crystalline. PZT thin films on a glass substrate had leakage current densities of about 10-8 A/cm2, acceptable hysteresis loop shapes with the remanent polarization (Pr) of 45 μC/cm2 and the coercive field (Ec) of 90 kV/cm. Ferroelectric properties on a glass substrate almost conform with those on a Si-based substrate.

  3. Flexible thin film magnetoimpedance sensors

    International Nuclear Information System (INIS)

    Kurlyandskaya, G.V.; Fernández, E.; Svalov, A.; Burgoa Beitia, A.; García-Arribas, A.; Larrañaga, A.

    2016-01-01

    Magnetically soft thin film deposited onto polymer substrates is an attractive option for flexible electronics including magnetoimpedance (MI) applications. MI FeNi/Ti based thin film sensitive elements were designed and prepared using the sputtering technique by deposition onto rigid and flexible substrates at different deposition rates. Their structure, magnetic properties and MI were comparatively analyzed. The main structural features were sufficiently accurately reproduced in the case of deposition onto cyclo olefine polymer substrates compared to glass substrates for the same conditions. Although for the best condition (28 nm/min rate) of the deposition onto polymer a significant reduction of the MI field sensitivity was found satisfactory for sensor applications sensitivity: 45%/Oe was obtained for a frequency of 60 MHz. - Highlights: • [FeNi/Ti] 3 /Cu/[FeNi/Ti] 3 films were prepared by sputtering at different deposition rates. • Polymer substrates insure sufficiently accurate reproducibility of the film structure. • High deposition rate of 28 nm/min insures the highest values of the magnetoimpedance sensitivity. • Deposition onto polymer results in the satisfactory magnetoimpedance sensitivity of 45%/Oe.

  4. Flexible thin film magnetoimpedance sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kurlyandskaya, G.V., E-mail: galina@we.lc.ehu.es [Universidad del País Vasco, UPV/EHU, Departamento de Electricidad y Electrónica, P.O. Box 644, Bilbao 48080 (Spain); Ural Federal University, Laboratory of Magnetic sensoric, Lenin Ave. 51, 620083 Ekaterinburg (Russian Federation); Fernández, E. [BCMaterials UPV-EHU, Vizcaya Science and Technology Park, 48160 Derio (Spain); Svalov, A. [Universidad del País Vasco, UPV/EHU, Departamento de Electricidad y Electrónica, P.O. Box 644, Bilbao 48080 (Spain); Ural Federal University, Laboratory of Magnetic sensoric, Lenin Ave. 51, 620083 Ekaterinburg (Russian Federation); Burgoa Beitia, A. [Universidad del País Vasco, UPV/EHU, Departamento de Electricidad y Electrónica, P.O. Box 644, Bilbao 48080 (Spain); García-Arribas, A. [Universidad del País Vasco, UPV/EHU, Departamento de Electricidad y Electrónica, P.O. Box 644, Bilbao 48080 (Spain); BCMaterials UPV-EHU, Vizcaya Science and Technology Park, 48160 Derio (Spain); Larrañaga, A. [SGIker, Servicios Generales de Investigación, Universidad del País Vasco (UPV/EHU), 48080 Bilbao (Spain)

    2016-10-01

    Magnetically soft thin film deposited onto polymer substrates is an attractive option for flexible electronics including magnetoimpedance (MI) applications. MI FeNi/Ti based thin film sensitive elements were designed and prepared using the sputtering technique by deposition onto rigid and flexible substrates at different deposition rates. Their structure, magnetic properties and MI were comparatively analyzed. The main structural features were sufficiently accurately reproduced in the case of deposition onto cyclo olefine polymer substrates compared to glass substrates for the same conditions. Although for the best condition (28 nm/min rate) of the deposition onto polymer a significant reduction of the MI field sensitivity was found satisfactory for sensor applications sensitivity: 45%/Oe was obtained for a frequency of 60 MHz. - Highlights: • [FeNi/Ti]{sub 3}/Cu/[FeNi/Ti]{sub 3} films were prepared by sputtering at different deposition rates. • Polymer substrates insure sufficiently accurate reproducibility of the film structure. • High deposition rate of 28 nm/min insures the highest values of the magnetoimpedance sensitivity. • Deposition onto polymer results in the satisfactory magnetoimpedance sensitivity of 45%/Oe.

  5. Room Temperature Tunable Multiferroic Properties in Sol-Gel-Derived Nanocrystalline Sr(Ti1−xFexO3−δ Thin Films

    Directory of Open Access Journals (Sweden)

    Yi-Guang Wang

    2017-09-01

    Full Text Available Sr(Ti1−xFexO3−δ (0 ≤ x ≤ 0.2 thin films were grown on Si(100 substrates with LaNiO3 buffer-layer by a sol-gel process. Influence of Fe substitution concentration on the structural, ferroelectric, and magnetic properties, as well as the leakage current behaviors of the Sr(Ti1−xFexO3−δ thin films, were investigated by using the X-ray diffractometer (XRD, atomic force microscopy (AFM, the ferroelectric test system, and the vibrating sample magnetometer (VSM. After substituting a small amount of Ti ion with Fe, highly enhanced ferroelectric properties were obtained successfully in SrTi0.9Ti0.1O3−δ thin films, with a double remanent polarization (2Pr of 1.56, 1.95, and 9.14 μC·cm−2, respectively, for the samples were annealed in air, oxygen, and nitrogen atmospheres. The leakage current densities of the Fe-doped SrTiO3 thin films are about 10−6–10−5 A·cm−2 at an applied electric field of 100 kV·cm−1, and the conduction mechanism of the thin film capacitors with various Fe concentrations has been analyzed. The ferromagnetic properties of the Sr(Ti1−xFexO3−δ thin films have been investigated, which can be correlated to the mixed valence ions and the effects of the grain boundary. The present results revealed the multiferroic nature of the Sr(Ti1−xFexO3−δ thin films. The effect of the annealing environment on the room temperature magnetic and ferroelectric properties of Sr(Ti0.9Fe0.1O3−δ thin films were also discussed in detail.

  6. Laser damage properties of TiO2/Al2O3 thin films grown by atomic layer deposition

    International Nuclear Information System (INIS)

    Wei Yaowei; Liu Hao; Sheng Ouyang; Liu Zhichao; Chen Songlin; Yang Liming

    2011-01-01

    Research on thin film deposited by atomic layer deposition (ALD) for laser damage resistance is rare. In this paper, it has been used to deposit TiO 2 /Al 2 O 3 films at 110 deg. C and 280 deg. C on fused silica and BK7 substrates. Microstructure of the thin films was investigated by x-ray diffraction. The laser-induced damage threshold (LIDT) of samples was measured by a damage test system. Damage morphology was studied under a Nomarski differential interference contrast microscope and further checked under an atomic force microscope. Multilayers deposited at different temperatures were compared. The results show that the films deposited by ALD had better uniformity and transmission; in this paper, the uniformity is better than 99% over 100 mm Φ samples, and the transmission is more than 99.8% at 1064 nm. Deposition temperature affects the deposition rate and the thin film microstructure and further influences the LIDT of the thin films. As to the TiO 2 /Al 2 O 3 films, the LIDTs were 6.73±0.47 J/cm 2 and 6.5±0.46 J/cm 2 at 110 deg. C on fused silica and BK7 substrates, respectively. The LIDTs at 110 deg. C are notably better than 280 deg. C.

  7. Growth of Fe2O3 thin films by atomic layer deposition

    International Nuclear Information System (INIS)

    Lie, M.; Fjellvag, H.; Kjekshus, A.

    2005-01-01

    Thin films of α-Fe 2 O 3 (α-Al 2 O 3 -type crystal structure) and γ-Fe 2 O 3 (defect-spinel-type crystal structure) have been grown by the atomic layer deposition (ALD) technique with Fe(thd) 3 (iron derivative of Hthd = 2,2,6,6-tetramethylheptane-3,5-dione) and ozone as precursors. It has been shown that an ALD window exists between 160 and 210 deg. C. The films have been characterized by various techniques and are shown to comprise (001)-oriented columns of α-Fe 2 O 3 with no in-plane orientation when grown on soda-lime-glass and Si(100) substrates. Good quality films have been made with thicknesses ranging from 10 to 130 nm. Films grown on α-Al 2 O 3 (001) and MgO(100) substrates have the α-Fe 2 O 3 and γ-Fe 2 O 3 crystal structure, respectively, and consist of highly oriented columns with in-plane orientations matching those of the substrates

  8. Effect of Different Deposition Power of In2O3 Target on the Characteristics of IGZO Thin Films Using the Cosputtering Method

    Directory of Open Access Journals (Sweden)

    Shang-Chao Hung

    2014-01-01

    Full Text Available The (In, Ga, ZnOx (IGZO thin films were deposited on glass substrates using cosputtering method in radio frequency magnetron sputtering system. Zn2Ga2O5 (Ga2O3-2 ZnO, GZO and In2O3 ceramics were used as targets and dual guns were used to deposit the IGZO thin films. Deposition power of GZO target was 80 W and deposition power of pure In2O3 target was changed from 70 W to 100 W, and the deposition time was 30 min. The effect of deposition power of In2O3 target on the crystalline, surface, electrical, and optical properties of the IGZO thin films was investigated at room temperature in a pure Ar atmosphere. The cosputtered IGZO thin films showed a very smooth and featureless surface and an amorphous structure regardless of the deposition power of In2O3 target due to the room temperature sputtering process. However, the cosputtered IGZO thin films exhibited transparent electrode properties because they had high transmittance ratio and low resistivity. The value variations in the optical band gap (Eg values of the IGZO thin film were evaluated from the plots of (αhν2=c(hν-Eg. We would also show that the deposition power of In2O3 target would have a large effect on mobility and Eg value of the IGZO thin films.

  9. THIN FILM-BASED SENSOR FOR MOTOR VEHICLE EXHAUST GAS, NH3, AND CO DETECTION

    Directory of Open Access Journals (Sweden)

    S. Sujarwata

    2016-10-01

    Full Text Available A copper phthalocyanine (CuPc thin film based gas sensor with FET structure and channel length 100 μm has been prepared by VE method and lithography technique to detect NH3, motor cycle exhaust gases and CO. CuPc material layer was deposited on SiO2 by the vacuum evaporator (VE method at room temperature and pressure of 8 x10-4 Pa. The stages of manufacturing gas sensor were Si/SiO2 substrate blenching with ethanol in an ultrasonic cleaner, source, and drain electrodes deposition on the substrate by using a vacuum evaporator, thin film deposition between the source/drain and gate deposition. The sensor response times to NH3, motorcycle exhaust gases and CO were 75 s, 135 s, and 150, respectively. The recovery times were 90 s, 150 s and 225, respectively. It is concluded that the CuPc thin film-based gas sensor with FET structure is the best sensor to detect the NH3 gas.Sensor gas berbasis film tipis copper phthalocyanine (CuPc berstruktur FET dengan panjang channel 100 μm telah dibuatdengan metode VE dan teknik lithography untuk mendeteksi NH3 gas buang kendaraan bermotor dan CO. Lapisan bahan CuPc dideposisikan pada permukaan silikon dioksida (SiO2 dengan metode vacuum evaporator (VE pada temperatur ruang dengan tekanan 8 x10-4 Pa. Tahapan pembuatan sensor gas adalah pencucian substrat Si/SiO2 dengan etanol dalam ultrasonic cleaner, deposisi elektroda source dan drain di atas substrat dengan metode vacuum evaporator, deposisi film tipis diantara source/drain dan deposisi gate. Waktu tanggap sensor terhadap NH3, gas buang kendaraan bermotor dan CO berturut-turut adalah 75 s, 135 s,dan 150 s. Waktu pemulihan berturut-turut adalah 90 s, 150 s,dan 225 s. Disimpulkan bahwa sensor gas berstruktur FET berbasis film tipis CuPc merupakan sensor paling baik untuk mendeteksi adanya gas NH3.

  10. Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells

    Directory of Open Access Journals (Sweden)

    Wang Lan

    2016-01-01

    Full Text Available We report a route to deposit In2S3 thin films from air-stable, low-cost molecular precursor inks for Cd-free buffer layers in chalcopyrite-based thin film solar cells. Different precursor compositions and processing conditions were studied to define a reproducible and robust process. By adjusting the ink properties, this method can be applied in different printing and coating techniques. Here we report on two techniques, namely spin-coating and inkjet printing. Active area efficiencies of 12.8% and 12.2% have been achieved for In2S3-buffered solar cells respectively, matching the performance of CdS-buffered cells prepared with the same batch of absorbers.

  11. Growth of C60 thin films on Al2O3/NiAl(100) at early stages

    Science.gov (United States)

    Hsu, S.-C.; Liao, C.-H.; Hung, T.-C.; Wu, Y.-C.; Lai, Y.-L.; Hsu, Y.-J.; Luo, M.-F.

    2018-03-01

    The growth of thin films of C60 on Al2O3/NiAl(100) at the earliest stage was studied with scanning tunneling microscopy and synchrotron-based photoelectron spectroscopy under ultrahigh-vacuum conditions. C60 molecules, deposited from the vapor onto an ordered thin film of Al2O3/NiAl(100) at 300 K, nucleated into nanoscale rectangular islands, with their longer sides parallel to direction either [010] or [001] of NiAl. The particular island shape resulted because C60 diffused rapidly, and adsorbed and nucleated preferentially on the protrusion stripes of the crystalline Al2O3 surface. The monolayer C60 film exhibited linear protrusions of height 1-3 Å, due to either the structure of the underlying Al2O3 or the lattice mismatch at the boundaries of the coalescing C60 islands; such protrusions governed also the growth of the second layer. The second layer of the C60 film grew only for a C60 coverage >0.60 ML, implying a layer-by-layer growth mode, and also ripened in rectangular shapes. The thin film of C60 was thermally stable up to 400 K; above 500 K, the C60 islands dissociated and most C60 desorbed.

  12. Antimony sulfide thin films prepared by laser assisted chemical bath deposition

    International Nuclear Information System (INIS)

    Shaji, S.; Garcia, L.V.; Loredo, S.L.; Krishnan, B.

    2017-01-01

    Highlights: • Antimony sulfide thin films were prepared by normal CBD and laser assisted CBD. • Characterized these films using XRD, XPS, AFM, optical and electrical measurements. • Accelerated growth was observed in the laser assisted CBD process. • These films were photoconductive. - Abstract: Antimony sulfide (Sb_2S_3) thin films were prepared by laser assisted chemical bath deposition (LACBD) technique. These thin films were deposited on glass substrates from a chemical bath containing antimony chloride, acetone and sodium thiosulfate under various conditions of normal chemical bath deposition (CBD) as well as in-situ irradiation of the chemical bath using a continuous laser of 532 nm wavelength. Structure, composition, morphology, optical and electrical properties of the Sb_2S_3 thin films produced by normal CBD and LACBD were analyzed by X-Ray diffraction (XRD), Raman Spectroscopy, Atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS), UV–vis spectroscopy and Photoconductivity. The results showed that LACBD is an effective synthesis technique to obtain Sb_2S_3 thin films for optoelectronic applications.

  13. Antimony sulfide thin films prepared by laser assisted chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Shaji, S., E-mail: sshajis@yahoo.com [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, 66455 (Mexico); CIIDIT—Universidad Autónoma de Nuevo León, Apodaca, Nuevo León (Mexico); Garcia, L.V. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, 66455 (Mexico); Loredo, S.L. [Centro de Investigación en Materiales Avanzados (CIMAV), Unidad Monterrey, PIIT, Apodaca, Nuevo León (Mexico); Krishnan, B. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, 66455 (Mexico); CIIDIT—Universidad Autónoma de Nuevo León, Apodaca, Nuevo León (Mexico); and others

    2017-01-30

    Highlights: • Antimony sulfide thin films were prepared by normal CBD and laser assisted CBD. • Characterized these films using XRD, XPS, AFM, optical and electrical measurements. • Accelerated growth was observed in the laser assisted CBD process. • These films were photoconductive. - Abstract: Antimony sulfide (Sb{sub 2}S{sub 3}) thin films were prepared by laser assisted chemical bath deposition (LACBD) technique. These thin films were deposited on glass substrates from a chemical bath containing antimony chloride, acetone and sodium thiosulfate under various conditions of normal chemical bath deposition (CBD) as well as in-situ irradiation of the chemical bath using a continuous laser of 532 nm wavelength. Structure, composition, morphology, optical and electrical properties of the Sb{sub 2}S{sub 3} thin films produced by normal CBD and LACBD were analyzed by X-Ray diffraction (XRD), Raman Spectroscopy, Atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS), UV–vis spectroscopy and Photoconductivity. The results showed that LACBD is an effective synthesis technique to obtain Sb{sub 2}S{sub 3} thin films for optoelectronic applications.

  14. Electrical and piezoelectric properties of BiFeO3 thin films grown on SrxCa1−xRuO3-buffered SrTiO3 substrates

    KAUST Repository

    Yao, Yingbang

    2012-06-01

    (001)-oriented BiFeO 3 (BFO) thin films were grown on Sr xCa 1-xRuO 3- (SCRO; x = 1, 0.67, 0.33, 0) buffered SrTiO 3 (001) substrates using pulsed laser deposition. The microstructural, electrical, ferroelectric, and piezoelectric properties of the thin films were considerably affected by the buffer layers. The interface between the BFO films and the SCRO-buffer layer was found to play a dominant role in determining the electrical and piezoelectric behaviors of the films. We found that films grown on SrRuO 3-buffer layers exhibited minimal electrical leakage while films grown on Sr 0.33Ca 0.67RuO 3-buffer layers had the largest piezoelectric response. The origin of this difference is discussed. © 2012 American Institute of Physics.

  15. 12. International conference on thin films (ICTF 12). Book of Abstract

    International Nuclear Information System (INIS)

    Majkova, E.

    2002-09-01

    The publication has been set up as a proceedings of the conference dealing with thin films production and study of their properties. The conference was focused on the following topics: (1) Advanced deposition techniques; (2) Thin Film Growth; (3) Diagnostics, Structure - Properties Relationship; (4) Mechanical Properties and Stress; (5) Protective and Functional Coatings; (6) Micropatterning and Nanostructures; (7) EUV and Soft X-Ray Multilayers; (8) Magnetic Thin Films and Multilayers; (9) Organic Thin Films; (10) Thin Films for Electronics and Optics. In this proceedings totally 157 abstracts are published of which 126 are interest for INIS

  16. Interface control in BaTiO3 based supercapacitors

    Science.gov (United States)

    Maglione, Mario; Elissalde, Catherine; Chung, U.-Chan

    2010-03-01

    Core shell BaTiO3 based particles sintered using advanced processes provide a high control of grain boundaries in bulk composites. As a result, supercapacitor behavior was evidenced which came from the balance between inner grain conductivity and grain boundary dielectric barrier. Thanks to the core-shell structure of the starting particles, improved control of the effective dielectric parameters can be achieved.

  17. Reactive Coevaporation Synthesis and Characterization of SrTiO3 Thin Films

    Science.gov (United States)

    Yamaguchi, Hiromu; Matsubara, Shogo; Miyasaka, Yoichi

    1991-09-01

    SrTiO3 thin films were prepared by the reactive coevaporation method, where the Ti and Sr metals were evaporated in oxygen ambient with an E-gun and K-cell, respectively. A uniform depth profile in composition was achieved by altering the Ti evaporation rate according to the Sr evaporation rate change. A typical dielectric constant of 170 was measured on films of 75 nm in thickness. The in-situ annealing in oxygen plasma reduced the leakage current.

  18. Epitaxial growth and structural characterization of Pb(Fe1/2Nb1/2)O3 thin films

    International Nuclear Information System (INIS)

    Peng, W.; Lemee, N.; Holc, J.; Kosec, M.; Blinc, R.; Karkut, M.G.

    2009-01-01

    We have grown lead iron niobate thin films with composition Pb(Fe 1/2 Nb 1/2 )O 3 (PFN) on (0 0 1) SrTiO 3 substrates by pulsed laser deposition. The influence of the deposition conditions on the phase purity was studied. Due to similar thermodynamic stability spaces, a pyrochlore phase often coexists with the PFN perovskite phase. By optimizing the kinetic parameters, we succeeded in identifying a deposition window which resulted in epitaxial perovskite-phase PFN thin films with no identifiable trace of impurity phases appearing in the X-ray diffractograms. PFN films having thicknesses between 20 and 200 nm were smooth and epitaxially oriented with the substrate and as demonstrated by RHEED streaks which were aligned with the substrate axes. X-ray diffraction showed that the films were completely c-axis oriented and of excellent crystalline quality with low mosaicity (X-ray rocking curve FWHM≤0.09 deg.). The surface roughness of thin films was also investigated by atomic force microscopy. The root-mean-square roughness varies between 0.9 nm for 50-nm-thick films to 16 nm for 100-nm-thick films. We also observe a correlation between grain size, surface roughness and film thickness.

  19. Bulk photovoltaic effect in epitaxial (K, Nb) substituted BiFeO3 thin films

    Science.gov (United States)

    Agarwal, Radhe; Zheng, Fan; Sharma, Yogesh; Hong, Seungbum; Rappe, Andrew; Katiyar, Ram

    We studied the bulk photovoltaic effect in epitaxial (K, Nb) modified BiFeO3 (BKFNO) thin films using theoretical and experimental methods. Epitaxial BKFNO thin films were grown by pulsed laser deposition (PLD). First, we have performed first principles density function theory (DFT) using DFT +U method to calculate electronic band structure, including Hubbard-Ueff (Ueff =U-J) correction into Hamiltonian. The electronic band structure calculations showed a direct band gap at 1.9 eV and a defect level at 1.7 eV (in a 40 atom BKFNO supercell), sufficiently lower in comparison to the experimentally observed values. Furthermore, the piezoforce microscopy (PFM) measurements indicated the presence of striped polydomains in BKFNO thin films. Angle-resolved PFM measurements were also performed to find domain orientation and net polarization directions in these films. The experimental studies of photovoltaic effect in BKNFO films showed a short circuit current of 59 micro amp/cm2 and open circuit voltage of 0.78 V. We compared our experimental results with first principles shift current theory calculations of bulk photovoltaic effect (BPVE).The synergy between theory and experimental results provided a realization of significant role of BPVE in order to understand the photovoltaic mechanism in ferroelectrics.

  20. Misfit strain dependence of ferroelectric and piezoelectric properties of clamped (001) epitaxial Pb(Zr0.52,Ti0.48)O3 thin films

    Science.gov (United States)

    Nguyen, Minh D.; Dekkers, Matthijn; Houwman, Evert; Steenwelle, Ruud; Wan, Xin; Roelofs, Andreas; Schmitz-Kempen, Thorsten; Rijnders, Guus

    2011-12-01

    A study on the effects of the residual strain in Pb(Zr0.52Ti0.48)O3 (PZT) thin films on the ferroelectric and piezoelectric properties is presented. Epitaxial (001)-oriented PZT thin film capacitors are sandwiched between SrRuO3 electrodes. The thin film stacks are grown on different substrate-buffer-layer combinations by pulsed laser deposition. Compressive or tensile strain caused by the difference in thermal expansion of the PZT film and substrate influences the ferroelectric and piezoelectric properties. All the PZT stacks show ferroelectric and piezoelectric behavior that is consistent with the theoretical model for strained thin films in the ferroelectric r-phase. We conclude that clamped (001) oriented Pb(Zr0.52Ti0.48)O3 thin films strained by the substrate always show rotation of the polarization vector.

  1. Surface characterization of superconductive Nd1Ba2Cu3Oy thin films using scanning probe microscopes

    International Nuclear Information System (INIS)

    Ting, W.; Badaye, M.; Itti, R.; Morishita, T.; Koshizuka, N.; Tanaka, S.

    1996-01-01

    Recently, superconductive Nd 1 Ba 2 Cu 3 O y (Nd123) thin films with high superconducting transition temperature (T c ) have been successfully fabricated at the authors institute employing the standard laser ablation method. In this paper, they report parts of the results of surface characterization of the Nd123 thin films using an ultrahigh vacuum scanning tunneling microscope/spectroscopy (UHV-STM/STS) and an atomic force microscope (AFM) system operated in air. Clear spiral pattern is observed on the surfaces of Nd123 thin films by STM and AFM, suggesting that films are formed by two-dimensional island growth mode at the final growing stage. Contour plots of the spirals show that the step heights of the spirals are not always the integer or half integer numbers of the c-axis parameter of the structure. This implies that the surface natural termination layer of the films may not be unique. Surface atomic images of the as-prepared Nd123 thin films are obtained employing both STM and AFM. STS measurements show that most of the surfaces are semiconductive, or sometimes even metallic. The results of STS measurements together with the fact that they are able to see the surface atomic images using scanning probe microscopes suggest that exposure to air does not cause serious degradation to the as-prepared surfaces of Nd123 thin films

  2. Fatigue mechanism verified using photovoltaic properties of Pb(Zr0.52Ti0.48)O3 thin films

    Science.gov (United States)

    Wu, Ming; Li, Wei; Li, Junning; Wang, Shaolan; Li, Yaqi; Peng, Biaolin; Huang, Haitao; Lou, Xiaojie

    2017-03-01

    The photovoltaic effect and its evolution during electrical fatigue in Pb(Zr0.52Ti0.48)O3 (PZT) thin films have been investigated. It is found that the photovoltaic effect of the as-grown PZT thin film is highly affected by the asymmetric Schottky barriers, which can be tuned by applying an external electric field. During fatigue processes, both open-circuit voltage (Voc) and short-circuit current (Jsc) decrease considerably with the increase of the number of electrical cycles. This phenomenon could be ascribed to the degradation of the interfacial layer between the thin film and the electrode induced by highly energetic charge carriers injected from the electrode during bipolar cycling. Our work sheds light on the physical mechanism of both ferroelectric photovoltaics and polarization fatigue in thin-film ferroelectrics.

  3. Self-Limited Growth in Pentacene Thin Films.

    Science.gov (United States)

    Pachmajer, Stefan; Jones, Andrew O F; Truger, Magdalena; Röthel, Christian; Salzmann, Ingo; Werzer, Oliver; Resel, Roland

    2017-04-05

    Pentacene is one of the most studied organic semiconducting materials. While many aspects of the film formation have already been identified in very thin films, this study provides new insight into the transition from the metastable thin-film phase to bulk phase polymorphs. This study focuses on the growth behavior of pentacene within thin films as a function of film thickness ranging from 20 to 300 nm. By employing various X-ray diffraction methods, combined with supporting atomic force microscopy investigations, one crystalline orientation for the thin-film phase is observed, while three differently tilted bulk phase orientations are found. First, bulk phase crystallites grow with their 00L planes parallel to the substrate surface; second, however, crystallites tilted by 0.75° with respect to the substrate are found, which clearly dominate the former in ratio; third, a different bulk phase polymorph with crystallites tilted by 21° is found. The transition from the thin-film phase to the bulk phase is rationalized by the nucleation of the latter at crystal facets of the thin-film-phase crystallites. This leads to a self-limiting growth of the thin-film phase and explains the thickness-dependent phase behavior observed in pentacene thin films, showing that a large amount of material is present in the bulk phase much earlier during the film growth than previously thought.

  4. Emergent Topological Phenomena in Thin Films of Pyrochlore Iridates

    Science.gov (United States)

    Yang, Bohm-Jung; Nagaosa, Naoto

    2014-06-01

    Because of the recent development of thin film and artificial superstructure growth techniques, it is possible to control the dimensionality of the system, smoothly between two and three dimensions. In this Letter we unveil the dimensional crossover of emergent topological phenomena in correlated topological materials. In particular, by focusing on the thin film of pyrochlore iridate antiferromagnets grown along the [111] direction, we demonstrate that the thin film can have a giant anomalous Hall conductance, proportional to the thickness of the film, even though there is no Hall effect in 3D bulk material. Moreover, in the case of ultrathin films, a quantized anomalous Hall conductance can be observed, despite the fact that the system is an antiferromagnet. In addition, we uncover the emergence of a new topological phase, the nontrivial topological properties of which are hidden in the bulk insulator and manifest only in thin films. This shows that the thin film of correlated topological materials is a new platform to search for unexplored novel topological phenomena.

  5. Characterization of nanostructured Mn{sub 3}O{sub 4} thin films grown by SILAR method at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ubale, A.U., E-mail: ashokuu@yahoo.com [Nanostructure Thin Film Materials Laboratory, Department of Physics, Govt. Vidarbha Institute of Science and Humanities, VMV Road, Amravati 444604, Maharashtra (India); Belkhedkar, M.R. [Department of Physics, Shri Shivaji College, Akola 444003, Maharashtra (India); Sakhare, Y.S. [Nanostructure Thin Film Materials Laboratory, Department of Physics, Govt. Vidarbha Institute of Science and Humanities, VMV Road, Amravati 444604, Maharashtra (India); Singh, Arvind [National Centre for Nanomaterials and Nanotechnology, University of Mumbai, Santacruz, Mumbai, Maharashtra (India); Gurada, Chetan; Kothari, D.C. [Department of Physics, University of Mumbai, Santacruz, Mumbai, Maharashtra (India)

    2012-10-15

    A novel successive ionic layer adsorption and reaction method has been successfully employed to grow nanostructured conducting nearly transparent thin films of Mn{sub 3}O{sub 4} on to glass substrates at room temperature using MnCl{sub 2} and NaOH as cationic and anionic precursors. The structural and morphological characterizations of the as deposited Mn{sub 3}O{sub 4} films have been carried out by means of X-ray diffraction (XRD), Field Emission Scanning Electron Micrograph (FESEM), EDAX, Atomic Fore Microscopy (AFM) and Fourier Transform Infrared Spectrum (FTIR) analysis. The optical absorption and electrical resistivity measurements were carried out to investigate optical band gap and activation energy of Mn{sub 3}O{sub 4} films deposited by SILAR method. The optical band gap and activation energy of the as deposited film is found to be 2.70 and 0.14 eV respectively. The thermo-emf measurements of Mn{sub 3}O{sub 4} thin film confirm its p-type semiconducting nature. Highlights: Black-Right-Pointing-Pointer Nanostructured Mn{sub 3}O{sub 4} thin film is prepared by SILAR method at room temperature. Black-Right-Pointing-Pointer The film is nanocrystalline with orthorhombic structure of Mn{sub 3}O{sub 4}. Black-Right-Pointing-Pointer The XRD, FTIR, FESEM, EDX and AFM characterization confirms nanocrystalline nature. Black-Right-Pointing-Pointer Optical band gap, electrical resistivity and activation energy of film is reported. Black-Right-Pointing-Pointer A thermo-emf measurement confirms p-type conductivity of Mn{sub 3}O{sub 4} films.

  6. Ferroelectric BaTiO3 and LiNbO3 Nanoparticles Dispersed in Ferroelectric Liquid Crystal Mixtures: Electrooptic and Dielectric (Postprint)

    Science.gov (United States)

    2016-10-14

    strength for non- doped LF4 and LiNbO3/LF4 nanocolloids at temperature 30C. 146 R. K . SHUKLA ET AL. 6 Distribution A. Approved for public release (PA...AFRL-RX-WP-JA-2017-0210 FERROELECTRIC BaTiO3 AND LiNbO3 NANOPARTICLES DISPERSED IN FERROELECTRIC LIQUID CRYSTAL MIXTURES: ELECTROOPTIC...COMMAND UNITED STATES AIR FORCE Ferroelectric BaTiO3 and LiNbO3 nanoparticles dispersed in ferroelectric liquid crystal mixtures: Electrooptic and

  7. Highly constrained ferroelectric [BaTiO3](1−x)Λ/[BaZrO3]xΛ superlattices: X-ray diffraction and Raman spectroscopy

    International Nuclear Information System (INIS)

    Belhadi, J.; El Marssi, M.; Gagou, Y.; El Mendili, Y.; Bouyanfif, H.; Yuzyuk, Yu. I.; Raevski, I. P.; Wolfman, J.

    2014-01-01

    We report an x-ray diffraction (XRD) and a Raman-scattering investigation of ferroelectric/paraelectric superlattices [BaTiO 3 ] (1−x)Λ /[BaZrO 3 ] xΛ for which the composition varied, 0.15 ≤ x ≤ 0.85, while the superlattice (SL) modulation period Λ was kept constant at about 100 Å. The samples were epitaxially grown by pulsed laser deposition on MgO substrates buffered with La 0.5 Sr 0.5 CoO 3 . Based on the XRD analysis and on polarized Raman spectra, we have showed that the large strain in SLs induced ferroelectricity in BaZrO 3 (BZ) for all SLs, a material that is paraelectric in the bulk form at any temperature and in the single film. The induced polar axis in BZ layers is perpendicular to the plane of substrate while BaTiO 3 (BT) layers exhibit in-plane polar orientation. Raman spectroscopy revealed a lattice ordering in SLs due to the misfit strain generated by the large lattice mismatch between the alternating BZ and BT layers. This strain induced a huge upward frequency of the lowest E(1TO) soft mode from 60 cm −1 in the BT single film to 215 cm −1 in the SL with x = 0.85. These results show that in spite of relatively large periodicity of SLs, they are highly constrained and the variation of BZ ratio allowed modifying strains between layers. The temperature dependence of the Raman spectra for BT 0.3Λ /BZ 0.7Λ and BT 0.7Λ /BZ 0.3Λ samples revealed giant shift of the ferroelectric phase transition. The phase transition temperature was found to be upshifted by about 300 °C with respect to BT single crystal.

  8. Zn2+ in-situ substitution behavior during the formation of BaTiO3 coatings from plasma-sprayed powders collected in liquid nitrogen

    Science.gov (United States)

    Liu, Zhe; Xing, Zhiguo; Wang, Haidou; Xue, Zifan; Chen, Shuying; Cui, Xiufang; Jin, Guo

    2018-04-01

    The dielectric performance of BaTiO3 ceramic coatings is enhanced significantly by the addition of ZnO. In this study, the maximum relative permittivity value (εr ≈ 923) was measured in BaTiO3 coatings with ZnO added at 6 wt%. The Curie temperature (Tc) was in the range of 111 °C-121 °C for all of the ZnO-modified BaTiO3 coatings. Tc shifted to low temperatures as the ZnO content increased. Detailed analyses were performed to determine the phase composition and optical band gaps of powders collected in liquid nitrogen, which showed that the Zn2+ ions were incorporated into the BaTiO3 lattice where they substituted into the Ti4+ sites, and the composite powders (BaTiO3 + 6 wt% ZnO) tolerated high temperatures in the plasma beam. In addition, some residual Zn accumulated in the grain boundary in the form of ZnO. X-ray diffraction and Raman spectroscopy showed that the substitution led to changes in the compositional and structural properties. The red shift in the optical band gap of BaTiO3 indicated that the ZnTi'' defects caused by the dopants acted as carriers in the doped BaTiO3 coatings.

  9. Stoichiometry and local bond configuration of In{sub 2}S{sub 3}:Cl thin films by Rutherford backscattering spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Juma, Albert O., E-mail: jumaa@biust.ac.bw

    2016-10-15

    In{sub 2}S{sub 3} thin films deposited using chemical methods always contain residual elements from the precursors, which modify their properties. As buffer layers in solar cells, the residual elements in the In{sub 2}S{sub 3} layer affect the performance of these devices. The stoichiometry of In{sub 2}S{sub 3} thin films deposited by spray ion layer gas reaction (ILGAR) was studied as a function of the residual Cl from InCl{sub 3} precursor by varying the deposition parameters. The chemical formula was deduced from the elemental composition determined using Rutherford backscattering (RBS). Incomplete sulfurization of the precursor implies that residual Cl{sup −} remains bonded to the In{sup 3+} ions while some occupy interstitial and/or antisite positions in the In{sub 2}S{sub 3} matrix. This results in thin films with different stoichiometry, described by the formula In{sub 4}S{sub 6−x}Cl{sub 2x+2y}. This changes the local bond configuration and geometry and underpins the influence of residual Cl on the physical properties of In{sub 2}S{sub 3} thin films.

  10. Conditions for the growth of smooth La0.7Sr0.3MnO3 thin films by pulsed electron ablation

    International Nuclear Information System (INIS)

    Graziosi, P.; Prezioso, M.; Gambardella, A.; Kitts, C.; Rakshit, R.K.; Riminucci, A.; Bergenti, I.; Borgatti, F.; Pernechele, C.; Solzi, M.; Pullini, D.; Busquets-Mataix, D.; Dediu, V.A.

    2013-01-01

    We report on the optimisation of the growth conditions of manganite La 0.7 Sr 0.3 MnO 3 thin films prepared by Channel Spark Ablation (CSA). CSA belongs to pulsed electron deposition methods and its energetic and deposition parameters are quite similar to those of pulsed laser deposition. The method has been already proven to provide manganite films with good magnetic properties, but the films were generally relatively rough (a few nm coarseness). Here we show that increasing the oxygen deposition pressure with respect to previously used regimes, reduces the surface roughness down to unit cell size while maintaining a robust magnetism. We analyse in detail the effect of other deposition parameters, like accelerating voltage, discharging energy, chamber pressure and substrate temperature and provide on this basis a set of optimal conditions for the growth of atomically flat films. The thicknesses for which atomically flat surface was achieved is as high as about 10–20 nm, corresponding to films with room temperature magnetism. We believe such magnetic layers represent appealing and suitable electrodes for various spintronic devices. - Highlights: ► Atomically flat manganite thin films ► Robust ferromagnetism at room temperature ► Perovskite thin films deposited by channel spark ablation ► Magnetotransport and magnetometry comparison

  11. Properties of TiO2 prepared by acid treatment of BaTiO3

    International Nuclear Information System (INIS)

    Okada, Kiyoshi; Yanagisawa, Tomoki; Kameshima, Yoshikazu; Nakajima, Akira

    2007-01-01

    TiO 3 powders were prepared by acid treatment of BaTiO 3 and their properties were investigated. The BaTiO 3 powder was subjected to HNO 3 in concentrations ranging from 10 -3 to 8 M at 90 deg. C for 0.5-6 h. Dissolution of BaTiO 3 and precipitation of TiO 2 occurred at acid concentrations of 2-5 M. BaTiO 3 dissolves completely to form a clear solution at reaction times of 0.5-1 h, but a rutile precipitate is formed after 2 h of acid treatment. By contrast, anatase is precipitated by adjusting the pH of the clear solution to 2-3 using NaOH or NH 4 OH solution. The rutile crystals were small and rod-shaped, consisting of many small coherent domains connected by grain boundaries with small inclination angles and edge dislocations, giving them a high specific surface area (S BET ). With increasing HNO 3 concentration, the S BET value increased from 100 to 170 m 2 /g while the crystallite size decreased from 25 to 11 nm. The anatase crystals obtained here were very small equi-axial particles with a smaller crystallite size than the rutile and S BET values of about 270 m 2 /g (higher than the rutile samples). The photocatalytic activity of these TiO 2 was determined from the decomposition rate of Methylene Blue under ultraviolet irradiation. Higher decomposition rates were obtained with larger crystallite sizes resulting from heat treatment. The maximum decomposition rates were obtained in samples heated at 500-600 deg. C. The photocatalytic activity of the TiO 2 was found to depend more strongly on the sample crystallite size than on S BET

  12. Altering properties of cerium oxide thin films by Rh doping

    International Nuclear Information System (INIS)

    Ševčíková, Klára; Nehasil, Václav; Vorokhta, Mykhailo; Haviar, Stanislav; Matolín, Vladimír

    2015-01-01

    Highlights: • Thin films of ceria doped by rhodium deposited by RF magnetron sputtering. • Concentration of rhodium has great impact on properties of Rh–CeO x thin films. • Intensive oxygen migration in films with low concentration of rhodium. • Oxygen migration suppressed in films with high amount of Rh dopants. - Abstract: Ceria containing highly dispersed ions of rhodium is a promising material for catalytic applications. The Rh–CeO x thin films with different concentrations of rhodium were deposited by RF magnetron sputtering and were studied by soft and hard X-ray photoelectron spectroscopies, Temperature programmed reaction and X-ray powder diffraction techniques. The sputtered films consist of rhodium–cerium mixed oxide where cerium exhibits a mixed valency of Ce 4+ and Ce 3+ and rhodium occurs in two oxidation states, Rh 3+ and Rh n+ . We show that the concentration of rhodium has a great influence on the chemical composition, structure and reducibility of the Rh–CeO x thin films. The films with low concentrations of rhodium are polycrystalline, while the films with higher amount of Rh dopants are amorphous. The morphology of the films strongly influences the mobility of oxygen in the material. Therefore, varying the concentration of rhodium in Rh–CeO x thin films leads to preparing materials with different properties

  13. Thermal conductivities of thin, sputtered optical films

    International Nuclear Information System (INIS)

    Henager, C.H. Jr.; Pawlewicz, W.T.

    1991-05-01

    The normal component of the thin film thermal conductivity has been measured for the first time for several advanced sputtered optical materials. Included are data for single layers of boron nitride (BN), aluminum nitride (AIN), silicon aluminum nitride (Si-Al-N), silicon aluminum oxynitride (Si-Al-O-N), silicon carbide (SiC), and for dielectric-enhanced metal reflectors of the form Al(SiO 2 /Si 3 N 4 ) n and Al(Al 2 O 3 /AIN) n . Sputtered films of more conventional materials like SiO 2 , Al 2 O 3 , Ta 2 O 5 , Ti, and Si have also been measured. The data show that thin film thermal conductivities are typically 10 to 100 times lower than conductivities for the same materials in bulk form. Structural disorder in the amorphous or very fine-grained films appears to account for most of the conductivity difference. Conclusive evidence for a film/substrate interface contribution is presented

  14. Magnetic hysteresis of cerium doped bismuth ferrite thin films

    International Nuclear Information System (INIS)

    Gupta, Surbhi; Tomar, Monika; Gupta, Vinay

    2015-01-01

    The influence of Cerium doping on the structural and magnetic properties of BiFeO 3 thin films have been investigated. Rietveld refinement of X-ray diffraction data and successive de-convolution of Raman scattering spectra of Bi 1−x Ce x FeO 3 (BCFO) thin films with x=0–0.20 reflect the single phase rhombohedral (R3c) formation for x<0.08, whereas concentration-driven gradual structural phase transition from rhombohedral (R3c) to partial tetragonal (P4mm) phase follows for x≥0.08. All low wavenumber Raman modes (<300 cm −1 ) showed a noticeable shift towards higher wavenumber with increase in doping concentration, except Raman E-1 mode (71 cm −1 ), shows a minor shift. Sudden evolution of Raman mode at 668 cm −1 , manifested as A 1 -tetragonal mode, accompanied by the shift to higher wavenumber with increase in doping concentration (x) affirm partial structural phase transition. Anomalous wasp waist shaped (M–H) hysteresis curves with improved saturation magnetization (M s ) for BCFO thin films is attributed to antiferromagnetic interaction/hybridization between Ce 4f and Fe 3d electronic states. The contribution of both hard and soft phase to the total coercivity is calculated. Polycrystalline Bi 0.88 Ce 0.12 FeO 3 thin film found to exhibit better magnetic properties with M s =15.9 emu/g without any impure phase. - Highlights: • Synthesis of single phase Bi 1−x Ce x FeO 3 thin films with (x=0–0.2) on cost effective corning glass and silicon substrates using CSD technique. • Structural modification studies using Rietveld refinement of XRD and de-convolution of Raman spectra revealed partial phase transition from rhombohedral (R3c) to tetragonal (P4mm) phase. • Possible reasons for origin of pinched magnetic behavior of BCFO thin films are identified. • Contribution of both hard and soft magnetic phase in coercivity of BCFO thin films is calculated and practical applications of such materials exhibiting pinching behavior are conferred

  15. Magnetic hysteresis of cerium doped bismuth ferrite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Surbhi [Department of Physics and Astrophysics, University of Delhi (India); Tomar, Monika [Physics Department, Miranda House, University of Delhi (India); Gupta, Vinay, E-mail: drguptavinay@gmail.com [Department of Physics and Astrophysics, University of Delhi (India)

    2015-03-15

    The influence of Cerium doping on the structural and magnetic properties of BiFeO{sub 3} thin films have been investigated. Rietveld refinement of X-ray diffraction data and successive de-convolution of Raman scattering spectra of Bi{sub 1−x}Ce{sub x}FeO{sub 3} (BCFO) thin films with x=0–0.20 reflect the single phase rhombohedral (R3c) formation for x<0.08, whereas concentration-driven gradual structural phase transition from rhombohedral (R3c) to partial tetragonal (P4mm) phase follows for x≥0.08. All low wavenumber Raman modes (<300 cm{sup −1}) showed a noticeable shift towards higher wavenumber with increase in doping concentration, except Raman E-1 mode (71 cm{sup −1}), shows a minor shift. Sudden evolution of Raman mode at 668 cm{sup −1}, manifested as A{sub 1}-tetragonal mode, accompanied by the shift to higher wavenumber with increase in doping concentration (x) affirm partial structural phase transition. Anomalous wasp waist shaped (M–H) hysteresis curves with improved saturation magnetization (M{sub s}) for BCFO thin films is attributed to antiferromagnetic interaction/hybridization between Ce 4f and Fe 3d electronic states. The contribution of both hard and soft phase to the total coercivity is calculated. Polycrystalline Bi{sub 0.88}Ce{sub 0.12}FeO{sub 3} thin film found to exhibit better magnetic properties with M{sub s}=15.9 emu/g without any impure phase. - Highlights: • Synthesis of single phase Bi{sub 1−x}Ce{sub x}FeO{sub 3} thin films with (x=0–0.2) on cost effective corning glass and silicon substrates using CSD technique. • Structural modification studies using Rietveld refinement of XRD and de-convolution of Raman spectra revealed partial phase transition from rhombohedral (R3c) to tetragonal (P4mm) phase. • Possible reasons for origin of pinched magnetic behavior of BCFO thin films are identified. • Contribution of both hard and soft magnetic phase in coercivity of BCFO thin films is calculated and practical

  16. Perovskite phase thin films and method of making

    Science.gov (United States)

    Boyle, Timothy J.; Rodriguez, Mark A.

    2000-01-01

    The present invention comprises perovskite-phase thin films, of the general formula A.sub.x B.sub.y O.sub.3 on a substrate, wherein A is selected from beryllium, magnesium, calcium, strontium, and barium or a combination thereof; B is selected from niobium and tantalum or a combination thereof; and x and y are mole fractions between approximately 0.8 and 1.2. More particularly, A is strontium or barium or a combination thereof and B is niobium or tantalum or a combination thereof. Also provided is a method of making a perovskite-phase thin film, comprising combining at least one element-A-containing compound, wherein A is selected from beryllium, magnesium, calcium, strontium or barium, with at least one element-B-containing compound, wherein B niobium or tantalum, to form a solution; adding a solvent to said solution to form another solution; spin-coating the solution onto a substrate to form a thin film; and heating the film to form the perovskite-phase thin film.

  17. Nano-crystallization in ZnO-doped In_2O_3 thin films via excimer laser annealing for thin-film transistors

    International Nuclear Information System (INIS)

    Fujii, Mami N.; Ishikawa, Yasuaki; Bermundo, Juan Paolo Soria; Uraoka, Yukiharu; Ishihara, Ryoichi; Cingel, Johan van der; Mofrad, Mohammad R. T.; Kawashima, Emi; Tomai, Shigekazu; Yano, Koki

    2016-01-01

    In a previous work, we reported the high field effect mobility of ZnO-doped In_2O_3 (IZO) thin film transistors (TFTs) irradiated by excimer laser annealing (ELA) [M. Fujii et al., Appl. Phys. Lett. 102, 122107 (2013)]. However, a deeper understanding of the effect of ELA on the IZO film characteristics based on crystallinity, carrier concentrations, and optical properties is needed to control localized carrier concentrations for fabricating self-aligned structures in the same oxide film and to adequately explain the physical characteristics. In the case of as-deposited IZO film used as the channel, a high carrier concentration due to a high density of oxygen vacancies was observed; such a film does not show the required TFT characteristics but can act as a conductive film. We achieved a decrease in the carrier concentration of IZO films by crystallization using ELA. This means that ELA can form localized conductive or semi-conductive areas on the IZO film. We confirmed that the reason for the carrier concentration decrease was the decrease of oxygen-deficient regions and film crystallization. The annealed IZO films showed nano-crystalline phase, and the temperature at the substrate was substantially less than the temperature limit for flexible films such as plastic, which is 50°C. This paves the way for the formation of self-aligned structures and separately formed conductive and semi-conductive regions in the same oxide film.

  18. Structural and magnetic properties of La0.7Sr0.3MnO3 ferromagnetic thin film grown on PMN-PT by sol–gel method

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    2017-08-01

    Full Text Available We report the preparation of epitaxial La0.7Sr0.3MnO3 thin films grown on (001-oriented 0.72Pb(Mg1∕3Nb2∕3O3-0.28PbTiO3 substrates by the sol–gel technique. The phase structure, magnetic properties and magnetoresistance of the samples are investigated by using high solution X-ray diffraction, atomic force microscopy, physical property measurement system, respectively. The La0.7Sr0.3MnO3 thin films display a well-defined hysteresis loop and typical ferromagnetism behavior at lower temperature. High magnetoresistance at 5T of 42% appears at 227K for La0.7Sr0.3MnO3 thin film.

  19. Detecting properties of thin film superconducting bridges made of YBa2Cu3O7-x

    International Nuclear Information System (INIS)

    Kulikov, V.A.; Matveets, L.V.; Serebryakov, A.Yu.; Laptev, V.N.; Makhov, V.I.; Emel'yanenkov, D.G.; Inkin, Yu.N.

    1989-01-01

    Results of study of detecting properties of thin film YBa 2 Cu 3 O 7-x bridges, subjected to the effect of 8 mm SHF-radiation are presented. The transition temperatures of bridges were equal to 80-85 K. Current-voltage characteristics and response dependences of bridges with 67, 150 and 425 Ω resistances were measured. It is shown that thin film bridges of YBa 2 Cu 3 O 7-x , representing the system of weak bonds, demonstrate nonstationary Josephson effect and synchronization of weak bonds in bridge volume

  20. Growth of strained, ferroelectric NaNbO{sub 3} thin films by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Sellmann, Jan; Schwarzkopf, Jutta; Duk, Andreas; Kwasniewski, Albert; Schmidbauer, Martin; Fornari, Roberto [IKZ, Berlin (Germany)

    2012-07-01

    Due to its promising ferro-/piezoelectric properties and high Curie temperature NaNbO{sub 3} has attracted much attention. In contrast to bulk crystals, thin epitaxial films may incorporate and maintain a certain compressive or tensile lattice strain, depending on the used substrate/film combination. This deformation of the crystal lattice is known to strongly influence the ferroelectric properties of perovskites. In the case of NaNbO{sub 3} compressive strain is achieved in films deposited on NdGaO{sub 3} and SrTiO{sub 3} substrates while deposition on DyScO{sub 3} and TbScO{sub 3} leads to tensile in-plane strain. In order to characterize and practically apply the ferroelectric films, it is necessary to embed them in a capacitor structure for which we use pseudomorphically grown SrRuO{sub 3} as bottom electrodes. We report on the deposition of SrRuO{sub 3} and NaNbO{sub 3} single layers on SrTiO{sub 3}, DyScO{sub 3}, TbScO{sub 3} and NbGaO{sub 3} substrates by means of pulsed laser deposition. By adjusting the substrate temperature, the oxygen partial pressure and the laser frequency we have successfully deposited smooth, strained, single phase NaNbO{sub 3} thin films. Investigations of the films by atomic force microscopy and high resolution X-ray diffraction reveal the dependence of the surface morphology and the incorporated lattice strain on the deposition parameters and the lattice mismatch, respectively. All films exhibit piezoelectric properties, as proven by piezoresponse force microscopy.

  1. Formation of Ag nanoparticles in percolative Ag–PbTiO3 composite thin films through lead-rich Ag–Pb alloy particles formed as transitional phase

    International Nuclear Information System (INIS)

    Hu, Tao; Wang, Zongrong; Su, Yanbo; Tang, Liwen; Shen, Ge; Song, Chenlu; Han, Gaorong; Weng, Wenjian; Ma, Ning; Du, Piyi

    2012-01-01

    The Ag nanoparticle dispersed percolative PbTiO 3 ceramic thin film was prepared in situ by sol–gel method with excess lead introduced into a sol precursor. The influence of excess lead and the heat treatment time on the formation of Ag nanoparticles was investigated by energy dispersive X-ray spectra, scanning electron microscopy, X-ray diffraction, and ultraviolet–visible absorption spectra. Results showed that the excess lead introduced into the sol precursor was in favor of the crystallization of the thin film and in favor of formation of the perovskite phase without the pyrochlore phase. Lead-rich Ag–Pb alloy particles first formed in the thin films and then decomposed to become large numbers of Ag nanoparticles of about 3 nm in size in the thin films when the heat treatment time was longer than 2 min. The content of the Ag nanoparticles increased with increasing the heat treatment time. The percolative behavior appears typically in the Ag nanoparticle dispersed thin films. The dielectric constant of the thin film was about 3 times of that without Ag nanoparticles. - Highlights: ► The Ag nanoparticles formed in the PbTiO 3 percolative ceramic thin film. ► The Ag–Pb alloy particles formed as transitional phase during thin film preparation. ► The lead-rich Ag–Pb alloy particles decomposed to form Ag nanoparticles in the film. ► Permittivity of the thin film is 3 times higher than that without Ag nanoparticles.

  2. Down-conversion luminescence and its temperature-sensing properties from Er3+-doped sodium bismuth titanate ferroelectric thin films

    Science.gov (United States)

    Wang, Shanshan; Zheng, Shanshan; Zhou, Hong; Pan, Anlian; Wu, Guangheng; Liu, Jun-ming

    2015-11-01

    Here, we demonstrate outstanding temperature-sensing properties from Na0.5Bi0.49Er0.01TiO3 (NBT:Er) thin films. The perovskite phase for them is stable in the temperature range from 80 to 440 K. Interestingly, the Er doping enhances the ferroelectric polarization and introduces local dipolar, which are positive for temperature sensing. Pumped by a 488-nm laser, the NBT:Er thin films show strong green luminescence with two bands around 525 and 548 nm. The intensity ratio I 525/ I 548 can be used for temperature sensing, and the maximum sensitivity is about 2.3 × 10-3 K-1, higher than that from Er-doped silicon oxide. These suggest NBT:Er thin film is a promising candidate for temperature sensor.

  3. Structural and optical properties of WO{sub 3} sputtered thin films nanostructured by laser interference lithography

    Energy Technology Data Exchange (ETDEWEB)

    Castro-Hurtado, I., E-mail: ichurtado@ceit.es [CEIT and Tecnun (University of Navarra), Manuel de Lardizábal 15, 20018 San Sebastián (Spain); Tavera, T.; Yurrita, P.; Pérez, N. [CEIT and Tecnun (University of Navarra), Manuel de Lardizábal 15, 20018 San Sebastián (Spain); Rodriguez, A. [CIC microGUNE Goiru kalea 9, Polo de Innovación Garaia, 20500 Arrasate-Mondragón (Spain); Mandayo, G.G.; Castaño, E. [CEIT and Tecnun (University of Navarra), Manuel de Lardizábal 15, 20018 San Sebastián (Spain)

    2013-07-01

    A study of the influence of annealing temperature on the structural, morphological and optical properties of WO{sub 3} thin films is presented. The coatings are deposited by RF reactive magnetron sputtering and characterized by XRD analysis and FESEM. The XRD diagrams of the samples show a phase transition from tetragonal to monoclinic when the annealing temperature is raised from 800 to 900 °C. Moreover, the increase of the annealing temperature to 800 °C favors the presence of a granular structure on the surface of the film. A decrease in the optical energy band gap (3.65–3.5 eV and 3.5–3.05 eV for direct and indirect transitions respectively) with annealing temperature has been measured employing Tauc's relation. Furthermore, WO{sub 3} thin films are processed by laser interference lithography (LIL) and periodic nanostructures are obtained. The processed films are characterized by a hexagonal symmetry with a period of 340 nm and the diameter of the nanostructured holes of 150 nm. These films show improved morphological properties of interest in several applications (gas sensors, photonic crystals, etc.) independent of the annealing temperature.

  4. Characteristics and optical properties of iron ion (Fe{sup 3+})-doped titanium oxide thin films prepared by a sol-gel spin coating

    Energy Technology Data Exchange (ETDEWEB)

    Wang, M.C. [Faculty of Fragrance and Cosmetics, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Lin, H.J. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China)], E-mail: hjlin@nuu.edu.tw; Yang, T.S. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China)

    2009-04-03

    Titanium dioxide (TiO{sub 2}) thin films doping of various iron ion (Fe{sup 3+}) concentrations have been prepared on a glass substrate by the sol-gel spin coating process. Characteristics and optical properties of TiO{sub 2} thin films doping of various Fe content were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV-vis) and spectroscopic ellipsometry. The crystalline phase of TiO{sub 2} thin films comprised only the anatase TiO{sub 2}, but the crystallinity decreased when the Fe{sup 3+} content increased from 0 to 25.0 wt%. During the Fe{sup 3+} addition to 25.0 wt%, the phase of TiO{sub 2} thin film still maintained the amorphous state. The absorption edge of TiO{sub 2} thin films shifted towards longer wavelengths (i.e. red shifted) from 355 to 415 nm when the Fe{sup 3+}-doped concentration increased from 0 to 25.0 wt%. The values of the refractive index (n), and extinction coefficient (k), decreased with an increasing Fe{sup 3+} content. Moreover, the band-gap energy of TiO{sub 2} thin films also decreased from 3.29 to 2.83 eV with an increase in the Fe{sup 3+} content from 0 to 25.0 wt%.

  5. Temperature dependence of Raman scattering in β-(AlGa2O3 thin films

    Directory of Open Access Journals (Sweden)

    Xu Wang

    2016-01-01

    Full Text Available We report a detailed investigation on temperature-dependent Raman scattering of β-(AlGa2O3 thin films with different Al content (0-0.72 under the temperature range of 77-300 K. The temperature-dependent Raman shifts and linewidths of the phonon modes were obtained by employing Lorentz fitting. The linewidths broadening of phonon modes with the temperature can be well explained by a model involving the effects of thermal expansion, lattice-mismatch-induced strain, and decay of optical phonon into two and three phonons. It is clearly demonstrated dependence of the linewidths and decay process on the Al content in β-(AlGa2O3 thin films, which can provide an experimental basis for realization of (AlGa2O3-based optoelectronic device applications.

  6. Linear electro-optical properties of tetragonal BaTiO 3

    Indian Academy of Sciences (India)

    Linear optical susceptibility and clamped linear electro-optical tensor coefficients of tetragonal BaTiO3 are calculated using a formalism based on bond charge theory. Calculated values are in close agreement with experimental data. The covalent Ti–O bonds constituting distorted TiO6 octahedral groups are found to be ...

  7. Thin films for precision optics

    International Nuclear Information System (INIS)

    Araujo, J.F.; Maurici, N.; Castro, J.C. de

    1983-01-01

    The technology of producing dielectric and/or metallic thin films for high precision optical components is discussed. Computer programs were developed in order to calculate and register, graphically, reflectance and transmittance spectra of multi-layer films. The technology of vacuum evaporation of several materials was implemented in our thin-films laboratory; various films for optics were then developed. The possibility of first calculate film characteristics and then produce the film is of great advantage since it reduces the time required to produce a new type of film and also reduces the cost of the project. (C.L.B.) [pt

  8. BaTiO3-based nanolayers and nanotubes: first-principles calculations.

    Science.gov (United States)

    Evarestov, Robert A; Bandura, Andrei V; Kuruch, Dmitrii D

    2013-01-30

    The first-principles calculations using hybrid exchange-correlation functional and localized atomic basis set are performed for BaTiO(3) (BTO) nanolayers and nanotubes (NTs) with the structure optimization. Both the cubic and the ferroelectric BTO phases are used for the nanolayers and NTs modeling. It follows from the calculations that nanolayers of the different ferroelectric BTO phases have the practically identical surface energies and are more stable than nanolayers of the cubic phase. Thin nanosheets composed of three or more dense layers of (0 1 0) and (0 1 1[overline]) faces preserve the ferroelectric displacements inherent to the initial bulk phase. The structure and stability of BTO single-wall NTs depends on the original bulk crystal phase and a wall thickness. The majority of the considered NTs with the low formation and strain energies has the mirror plane perpendicular to the tube axis and therefore cannot exhibit ferroelectricity. The NTs folded from (0 1 1[overline]) layers may show antiferroelectric arrangement of Ti-O bonds. Comparison of stability of the BTO-based and SrTiO(3)-based NTs shows that the former are more stable than the latter. Copyright © 2012 Wiley Periodicals, Inc.

  9. Tuning the electronic properties at the surface of BaBiO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ferreyra, C. [GIyA y INN, CNEA, Av.Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Departamento de Física, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina); Guller, F.; Llois, A. M.; Vildosola, V. [GIyA y INN, CNEA, Av.Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Marchini, F.; Williams, F. J. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Departamento de Química Inorgánica, Analítica y Química-Física, INQUIMAE-CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, Buenos Aires (Argentina); Lüders, U. [CRISMAT, CNRS UMR 6508, ENSICAEN, 6 Boulevard Maréchal Juin, 14050 Caen Cedex 4 (France); Albornoz, C. [GIyA y INN, CNEA, Av.Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Leyva, A. G. [GIyA y INN, CNEA, Av.Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Escuela de Ciencia y Tecnología, UNSAM, Campus Miguelete, (1650), San Martín, Buenos Aires (Argentina); and others

    2016-06-15

    The presence of 2D electron gases at surfaces or interfaces in oxide thin films remains a hot topic in condensed matter physics. In particular, BaBiO{sub 3} appears as a very interesting system as it was theoretically proposed that its (001) surface should become metallic if a Bi-termination is achieved (Vildosola et al., PRL 110, 206805 (2013)). Here we report on the preparation by pulsed laser deposition and characterization of BaBiO{sub 3} thin films on silicon. We show that the texture of the films can be tuned by controlling the growth conditions, being possible to stabilize strongly (100)-textured films. We find significant differences on the spectroscopic and transport properties between (100)-textured and non-textured films. We rationalize these experimental results by performing first principles calculations, which indicate the existence of electron doping at the (100) surface. This stabilizes Bi ions in a 3+ state, shortens Bi-O bonds and reduces the electronic band gap, increasing the surface conductivity. Our results emphasize the importance of surface effects on the electronic properties of perovskites, and provide strategies to design novel oxide heterostructures with potential interface-related 2D electron gases.

  10. Preparation of Cu{sub 2}ZnSnS{sub 4} thin films by sulfurizing stacked precursor thin films via successive ionic layer adsorption and reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Su Zhenghua; Yan Chang; Sun Kaiwen; Han Zili [School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); Liu Fangyang, E-mail: liufangyang@csu.edu.cn [School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); Liu Jin [School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); Lai Yanqing, E-mail: laiyanqingcsu@163.com [School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); Li Jie; Liu Yexiang [School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China)

    2012-07-15

    Earth-abundant Cu{sub 2}ZnSnS{sub 4} is a promising alternative photovoltaic material which has been examined as absorber layer of thin film solar cells. In this study, Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films have been successfully fabricated by sulfurizing stacked precursor thin films via successive ionic layer adsorption and reaction (SILAR) method. The prepared CZTS thin films have been characterized by X-ray diffraction, energy dispersive spectrometer, Raman spectroscopy, UV-vis spectroscopy, Hall effect measurements and photoelectrochemical tests. Results reveal that the thin films have kesterite structured Cu{sub 2}ZnSnS{sub 4} and the p-type conductivity with a carrier concentration in the order of 10{sup 18} cm{sup -3} and an optical band gap of 1.5 eV, which are suitable for applications in thin film solar cells.

  11. Paraconductivity and excess Hall effect of YBa2Cu3Ox thin films

    International Nuclear Information System (INIS)

    Gueffaf, A.

    2001-10-01

    Superconducting YBa 2 Cu 3 O x thin films were produced by in situ off-axis RF magnetron sputter deposition using a stoichiometric single target (T1). The effects of individual deposition parameters on the film properties are discussed. The transition temperatures for films deposited on MgO (100) are slightly lower than that for the SrTiO 3 and LaAlO 3 (100)-oriented substrates. The lower transition temperatures in the MgO substrates are most likely the result of the larger lattice mismatch with YBa 2 Cu 3 O x . All films grown on (100) substrates are c-axis oriented. The orientation of the sputtered YBCO films appears to depend only on the substrate orientation and not on the substrate material choice. Typical results for the c-axis lattice parameter c for various YBCO thin films sputtered onto SrTiO 3 , LaAIO 3 and MgO all (100)-oriented substrates with a range of T c values are presented. Three different targets were used in the course of this work: the first one (T1) was a 60 mm diameter, 3 mm thickness high density commercial YBCO disc; the second one (T2) was a 35 mm diameter, 4 mm thickness high density YBCO disc; and the third one (T3) was a 60 mm diameter, 3 mm thickness YBCO powder pressed then sintered on a copper plate substrate. The latter two were manufactured in house and are reported here for the first time. The best results were obtained using T1. The best films had T c (onset)= 89-93 K close to that of bulk YBCO and a transition width ΔT c =2-5 K. But some other films exhibited lower critical temperatures T c (onset)= 62-70 K and broader transitions ΔT c = 10.4-13.6 K. These reductions in T c and the broadening of the transition are due to oxygen deficiency. This is shown by the c-axis lattice parameter calculations. All films grown using T2 and T3 exhibited lower critical temperatures and broader transitions for the same reason. A novel heater element was manufactured and a previous heater design was modified for adaptation of the new element

  12. Analysis of Hard Thin Film Coating

    Science.gov (United States)

    Shen, Dashen

    1998-01-01

    MSFC is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit hard thin film an stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  13. Thin-film solar cell

    NARCIS (Netherlands)

    Metselaar, J.W.; Kuznetsov, V.I.

    1998-01-01

    The invention relates to a thin-film solar cell provided with at least one p-i-n junction comprising at least one p-i junction which is at an angle alpha with that surface of the thin-film solar cell which collects light during operation and at least one i-n junction which is at an angle beta with

  14. Evidence of Room Temperature Ferromagnetism Due to Oxygen Vacancies in (In1- x Fe x )2O3 Thin Films

    Science.gov (United States)

    Chakraborty, Deepannita; Munuswamy, Kuppan; Shaik, Kaleemulla; Nasina, Madhusudhana Rao; Dugasani, Sreekantha Reddy; Inturu, Omkaram

    2018-03-01

    Iron substituted indium oxide (In1- x Fe x )2O3 thin films at x = 0.00, 0.03, 0.05 and 0.07 were coated onto Corning 7059 glass substrates using the electron beam evaporation technique followed by annealing at different temperatures. The prepared thin films were subjected to different characterization techniques to study their structural, optical and magnetic properties. The structural properties of the thin films were studied using x-ray diffractometry (XRD). From the XRD results it was found that the films were crystallized in cubic structure, and no change in crystal structure was observed with annealing temperature. No secondary phases related to iron were observed from the XRD profiles. The chemical composition and surface morphology of the films were examined by field emission scanning electron microscope (FE-SEM) attached with energy dispersive analysis of x-ray (EDAX). The valence state of the elements were studied by x-ray photoelectron spectroscopy (XPS) and found that the indium, iron and oxygen were in In+3, Fe+3 and O-2 states. From the data, the band gap of the (In1- x Fe x )2O3 thin films were calculated and it increased with increase of annealing temperature. The magnetic properties of the films were studied at room temperature by vibrating sample magnetometer (VSM). The films exhibited ferromagnetism at room temperature.

  15. Electrical transport properties of MoO{sub 3} thin films prepared by laser assisted evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Carreno, L.D.; Pardo, A.; Zuluaga, M.; Torres, J.; Alfonso, J.E. [Group of Materials with Technological Applications, GMAT, Physics Department, Universidad Nacional de Colombia, Bogota (Colombia); Cortes-Bracho, O.L. [Group of Materials with Technological Applications, GMAT, Physics Department, Universidad Nacional de Colombia, Bogota (Colombia); Electronic Engineering Department, Universidad Nacional de Colombia, Bogota (Colombia)

    2007-07-01

    In the present paper the growth of MoO{sub 3} thin films on common glass substrates are described. The films were prepared by evaporation of a MoO{sub 3} target with a CO{sub 2} laser (10.6 {mu}m), operating in the continuous wave mode. The effect of substrate temperature on the crystallographic structure and electrical properties of MoO{sub 3} thin films was studied. The chemical composition of the different species formed on the films surface was obtained by X-ray photoelectron spectroscopy (XPS) and the crystalline structure was studied with X-ray diffraction (XRD). The electrical conductivity of the films was determined using the standard four-points method. Conductivity of the films varied from de 10{sup -9} to 10{sup -5} ({omega}cm){sup -1} in the 300-600 K temperature range. Arrhenius-type plots for the electrical conductivity indicate the presence of at least two different conduction mechanisms. The I-V characteristic curve shows an ohmic behavior only in the 4.5-60 V range. Outside this interval the I-V curve has a behavior described by a power law. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Epitaxial growth of cubic Gd{sub 2}O{sub 3} thin films on Ge substrates

    Energy Technology Data Exchange (ETDEWEB)

    Molle, A; Wiemer, C; Bhuiyan, M D N K; Tallarida, G; Fanciulli, M [CNR-INFM, Laboratorio Nazionale MDM, via C. Olivetti 2, I-20041 Agrate Brianza (Italy)], E-mail: alessandro.molle@mdm.infm.it

    2008-03-15

    Gd{sub 2}O{sub 3} thin films were grown on Ge (001) substrates by molecular beam epitaxy. The epitaxial character of the film is demonstrated by electron diffraction during the growth. The structural characterization of the films shows that the Gd{sub 2}O{sub 3} forms a bixbyite polymorph with a (110) out-of-plane orientation. The formation of bixbyite structured Gd{sub 2}O{sub 3} is discussed in terms of the atomic arrangement of the oxide planes on the Ge(001) surface.

  17. Surface-potential undulation of Alq3 thin films prepared on ITO, Au, and n-Si.

    Science.gov (United States)

    Ozasa, Kazunari; Ito, Hiromi; Maeda, Mizuo; Hara, Masahiko

    2012-01-01

    The surface potential (SP) morphology on thin films of tris(8-hydroxyquinolinato) aluminum (Alq3) was investigated with Kelvin probe force microscopy. Thin Alq3 films of 100 nm were prepared on ITO/glass substrates, Au/mica substrates, and n-Si substrates. Cloud-like morphologies of the SP undulation with 200-400 nm in lateral size were observed for all three types of the substrates. New larger peaks were observed in the cloud-like morphologies when the surfaces were exposed shortly to a light, while the SP average was reduced monotonically. The nonuniform distribution of charged traps and mobility was deduced from the SP undulation morphology and its photoexposure dependences.

  18. Thin-Film Material Science and Processing | Materials Science | NREL

    Science.gov (United States)

    Thin-Film Material Science and Processing Thin-Film Material Science and Processing Photo of a , a prime example of this research is thin-film photovoltaics (PV). Thin films are important because cadmium telluride thin film, showing from top to bottom: glass, transparent conducting oxide (thin layer

  19. Comparative study on substitution effects in BiFeO{sub 3} thin films fabricated on FTO substrates by chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Xu; Tan, Guoqiang, E-mail: tan3114@163.com; Hao, Hangfei; Ren, Huijun

    2013-10-01

    Pure BiFeO{sub 3} (BFO), BiFe{sub 0.97}Co{sub 0.03}O{sub 3−δ} (BFCO) and Bi{sub 0.90}Gd{sub 0.10}Fe{sub 0.97}Co{sub 0.03}O{sub 3−δ} (BGFCO) thin films were successfully deposited on FTO substrates by chemical solution deposition technique. The field emission scanning electron microscope reveals that the surface morphology of the BGFCO thin film becomes more compact and uniform than that of the other two films. A slight lattice distortion is created in the BFCO thin film, whereas 10% Gd doping gives rise to tetragonal phase transition and (1 1 0) preferentially oriented film texture for the BGFCO thin film, as evidenced by Raman scattering spectra and X-ray diffraction analyses. X-ray photoelectron spectroscopy analyses clarify that Co-doping results in the increase of oxygen vacancy concentration in the BFCO film, while further introduction of Gd into the BFCO lattice can decrease oxygen vacancy concentration, and the concentrations of Fe{sup 2+} ions in the BFCO and BGFCO thin films are less than that in the BFO counterpart. The BFCO film shows the improved remanent polarization (P{sub r}) of 11.2 μC/cm{sup 2} compared with that of 1.4 μC/cm{sup 2} for the BFO film. The high breakdown strength, low leakage current density in the high electric filed, improved dielectric properties as well as the increased stereochemical activity of Bi ion lone electron pair of the BGFCO thin film all together contribute to the giant P{sub r} of 139.6 μC/cm{sup 2} at room temperature.

  20. 130 MeV Au ion irradiation induced dewetting on In2Te3 thin film

    International Nuclear Information System (INIS)

    Matheswaran, P.; Abhirami, K.M.; Gokul, B.; Sathyamoorthy, R.; Prakash, Jai; Asokan, K.; Kanjilal, D.

    2012-01-01

    Highlights: ► In 2 Te 3 phase formed from In/Te bilayer by 130 MeV Au ion irradiation. ► Lower fluence results mixed phases with initial state of dewetting. ► At higher fluence, In 2 Te 3 phase with complete dewetting pattern is formed. ► Thermal spike model is used to explain the inter face mixing phenomena. ► SHI irradiation may be used to functionalize the structural and surface properties of thin films. - Abstract: In/Te bilayer thin films were prepared by sequential thermal evaporation and subsequently irradiated by 130 MeV Au ions. The pristine and irradiated samples were characterized by X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. RBS spectra reveal the sputtering of Te film and interface mixing, with increasing fluence. The surface morphology showed the beginning of dewetting of Te thin film and formation of the partially connected with the mixed zones at the fluence of 1 × 10 13 ions/cm 2 . At the higher fluence of 3 × 10 13 ions/cm 2 , dewetted structures were isolated at the surface. Above results are explained based on the formation of craters, sputtering and dewetting followed by inter-diffusion at the interface of molten zones due to thermal spike induced by Au ions.

  1. Valence control of cobalt oxide thin films by annealing atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Wang Shijing [School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Beijing 100083 (China); Zhang Boping, E-mail: bpzhang@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyua